Has anyone found a way to automate the update amortization step for secondary books when you are using amortizations? I think if you use items you can set a template for the secondary book but what if you just are booking expenses on a vendor bill?

I looked into this extensively and there are really no good solutions. Worked with some devs who confirmed at least at the time (a couple years ago) that there's no way to script to or on that Update Amortization Schedule window. The "best" solution I was able to figure out was to grab the amortization template + dates if they're filled in on the bill and generate book specific JE(s) based on that info for secondary books. Then link the JEs back to the original Bill so you have references all on the originating transaction. I think the plan was to hide the Update Amortization button too so someone didn't accidentally do both. Although that was the draft we had worked out (a dev signed off on this being possible), we never ended up building it, so I can't give you code. It's pretty stupid that 5+ years after the release of ARM/Multibook, they haven't separated out the features so turning on that feature for the revenue side doesn't also do it for the expense side. IIRC that info isn't even exposed via the API so even if you have some 3rd party AP service (billing.com, Tipalti, etc), their product can't set that either.

yeah this is what I have found too. Thanks for your reply! the solution for the JEs are you saying that you were going to amortize the transactions manually with a book specific JE or are you saying that you were going to recreate the transaction with a book specific JE and then amortize that? If the latter were you going to first clear the previous transaction and then rebook it on the JE so that the bill was not double booked?

the premise of secondary book is based on modification of item settings, thus expense line has not much to do with it 😞.

you were going to recreate the transaction with a book specific JE and then amortize that? If the latter were you going to first clear the previous transaction and then rebook it on the JE so that the bill was not double booked?

Yes that one @Keith Weaver The plan was to basically replicate with a book specific JE what happens when you fill in the info on the Update Amortization screen. Depending on how you set up your Amortization template, setting that info on a bill will change your GL postings and create the secondary book amortization schedule. So basically the plan was that we'd put in a book specific JE that would replicate the GL impact changes that happen on the bill when you fill in the Update Amortization window to create a secondary book amortization schedule. You can create an amortization schedule off of a JE, so we were just setting the GL lines on the JE to be what they needed to be for the ending GL impact to be correct, and then filling in the Name (vendor), Amortization Template, Start Date and End Date on the applicable line. End result is you get two identical amortization schedules, one in each book, just like you get if you fill in the Update Amortization window. They just end up originating from two different transactions rather than all from the bill. It's clunky, but I think it would work. It worked when I went through it manually anyway. I don't recall the complexity level to script it.