Posting to jobs always creates job ledger entries. The entries are either debits or credits depending on whether they increase your costs or represent sales to a customer. In the Inventory area, sales and negative adjustments create credit item entries and purchases and positive adjustments create debit items. The Jobs area is similar.
Open Entries
Every entry posted in the context of a job is an open entry when the amount in the Remaining Amount field in the Job Ledger Entry table is not zero. If you post an entry in the job journal without placing a check x in the Chargeable field, the remaining amount will be zero and the entry will not be open.
Positive Entries
Entries in the job journal, sales credit memos and purchase invoices create positive job ledger entries. This requires that the posted quantities and prices be positive values. Entries posted in these parts of the application cause an increase of your costs. The posting routines determine that an entry will be a positive one when the Total Price field in the Job Ledger Entry table contains a positive amount.
Negative Entries
Entries in a purchase credit memo or a sales invoice create negative job ledger entries. Entries posted in these parts of the application can be applied to your costs.