For one of our customers we only use write-in products for the sales orders. (Some of you may wonder why do we use built-in sales orders in the first place but it eeez what it eeez). What I did notice is that the sales order entity will not recalculate manual items until the price list is set even though it absolutely irrelevant for the write-in products. Ah, blast, let me create a dummy price list and use it. Problem solved.
Except it’s a hasty solution for an RTFM issue. Not quite sure when did this flag make the first appearance, maybe even in CRM 1.2 but price list can be made optional in Dynamics 365 Sales. Just follow the instructions.
This week resolution: go out and deal with real issues more often.