diff --git a/client/src/components/job-detail-lines/job-lines.component.jsx b/client/src/components/job-detail-lines/job-lines.component.jsx
index 67e8381c9..965839c55 100644
--- a/client/src/components/job-detail-lines/job-lines.component.jsx
+++ b/client/src/components/job-detail-lines/job-lines.component.jsx
@@ -160,7 +160,7 @@ export function JobLinesComponent({
       render: (text, record) => (
         <>
           <CurrencyFormatter>{record.act_price}</CurrencyFormatter>
-          {record.prt_dsmk_p !== 0 && (
+          {record.prt_dsmk_p && record.prt_dsmk_p !== 0 && (
             <span
               style={{ marginLeft: ".2rem" }}
             >{`(${record.prt_dsmk_p}%)`}</span>
diff --git a/client/src/components/job-lines-upsert-modal/job-lines-upsert-modal.component.jsx b/client/src/components/job-lines-upsert-modal/job-lines-upsert-modal.component.jsx
index 07e9cc009..a2fa6b8ac 100644
--- a/client/src/components/job-lines-upsert-modal/job-lines-upsert-modal.component.jsx
+++ b/client/src/components/job-lines-upsert-modal/job-lines-upsert-modal.component.jsx
@@ -210,6 +210,13 @@ export default function JobLinesUpsertModalComponent({
           >
             <InputCurrency precision={2} min={0} />
           </Form.Item>
+          <Form.Item
+            label={t("joblines.fields.prt_dsmk_p")}
+            name="prt_dsmk_p"
+            initialValue={0}
+          >
+            <InputCurrency precision={0} min={0} max={100} />
+          </Form.Item>
         </LayoutFormRow>
       </Form>
     </Modal>
diff --git a/hasura/migrations/1622571272382_alter_table_public_joblines_alter_column_prt_dsmk_p/down.yaml b/hasura/migrations/1622571272382_alter_table_public_joblines_alter_column_prt_dsmk_p/down.yaml
new file mode 100644
index 000000000..106fafc7e
--- /dev/null
+++ b/hasura/migrations/1622571272382_alter_table_public_joblines_alter_column_prt_dsmk_p/down.yaml
@@ -0,0 +1,5 @@
+- args:
+    cascade: false
+    read_only: false
+    sql: ALTER TABLE ONLY "public"."joblines" ALTER COLUMN "prt_dsmk_p" DROP DEFAULT;
+  type: run_sql
diff --git a/hasura/migrations/1622571272382_alter_table_public_joblines_alter_column_prt_dsmk_p/up.yaml b/hasura/migrations/1622571272382_alter_table_public_joblines_alter_column_prt_dsmk_p/up.yaml
new file mode 100644
index 000000000..1b845543f
--- /dev/null
+++ b/hasura/migrations/1622571272382_alter_table_public_joblines_alter_column_prt_dsmk_p/up.yaml
@@ -0,0 +1,6 @@
+- args:
+    cascade: false
+    read_only: false
+    sql: ALTER TABLE ONLY "public"."joblines" ALTER COLUMN "prt_dsmk_p" SET DEFAULT
+      0;
+  type: run_sql
diff --git a/hasura/migrations/1622571551101_run_sql_migration/down.yaml b/hasura/migrations/1622571551101_run_sql_migration/down.yaml
new file mode 100644
index 000000000..fe51488c7
--- /dev/null
+++ b/hasura/migrations/1622571551101_run_sql_migration/down.yaml
@@ -0,0 +1 @@
+[]
diff --git a/hasura/migrations/1622571551101_run_sql_migration/up.yaml b/hasura/migrations/1622571551101_run_sql_migration/up.yaml
new file mode 100644
index 000000000..579fcb8c2
--- /dev/null
+++ b/hasura/migrations/1622571551101_run_sql_migration/up.yaml
@@ -0,0 +1,5 @@
+- args:
+    cascade: false
+    read_only: false
+    sql: "update joblines \nset prt_dsmk_p = 0 where joblines.prt_dsmk_p is null;"
+  type: run_sql
diff --git a/server/job/job-costing.js b/server/job/job-costing.js
index 3f67bc36a..179b96d4d 100644
--- a/server/job/job-costing.js
+++ b/server/job/job-costing.js
@@ -314,7 +314,7 @@ function GenerateCostingData(job) {
                 amount: Math.round((val.act_price || 0) * 100),
               })
                 .multiply(val.part_qty || 0)
-                .percentage(val.prt_dsmk_p)
+                .percentage(val.prt_dsmk_p || 0)
             );
           if (!acc.parts[partsProfitCenter])
             acc.parts[partsProfitCenter] = Dinero();
@@ -343,7 +343,7 @@ function GenerateCostingData(job) {
                   amount: Math.round((val.act_price || 0) * 100),
                 })
                   .multiply(val.part_qty || 0)
-                  .percentage(val.prt_dsmk_p)
+                  .percentage(val.prt_dsmk_p || 0)
               );
 
             if (!acc.parts[partsProfitCenter])
diff --git a/server/job/job-totals.js b/server/job/job-totals.js
index 45f6bb4e5..ee9d76aca 100644
--- a/server/job/job-totals.js
+++ b/server/job/job-totals.js
@@ -217,7 +217,7 @@ function CalculatePartsTotals(jobLines) {
                     amount: Math.round((value.act_price || 0) * 100),
                   })
                     .multiply(value.part_qty || 0)
-                    .percentage(value.prt_dsmk_p)
+                    .percentage(value.prt_dsmk_p || 0)
                 ),
                 list: {
                   ...acc.parts.list,
@@ -248,7 +248,7 @@ function CalculatePartsTotals(jobLines) {
                       amount: Math.round((value.act_price || 0) * 100),
                     })
                       .multiply(value.part_qty || 0)
-                      .percentage(value.prt_dsmk_p)
+                      .percentage(value.prt_dsmk_p || 0)
                   ),
               },
             };
@@ -382,7 +382,7 @@ function CalculateTaxesTotals(job, otherTotals) {
                 amount: Math.round((val.act_price || 0) * 100),
               })
                 .multiply(val.part_qty || 0)
-                .percentage(val.prt_dsmk_p)
+                .percentage(val.prt_dsmk_p || 0)
             )
             .percentage(
               ((job.parts_tax_rates &&