Billing Line not posting to COPA

Hi,

I have a requirement where I need to change the GL accounts for some lines that are being billed.

So, for example, if the line being billed is supposed to post to 100000, I will change it to 200000…. based on some other criteria my business came up with. The requirements make it impossible to handle via regular config...

The change we did is on include ZXVVFU08 and what we do is change the value on ACCIT-HKONT for the corresponding lines.

This change is affecting CO-PA postings somehow and this is what I would like to figure out…

If I leave the GL account derived from the system, it posts the line to COPA… if I make this mentioned substitution, the line won’t post to COPA.... all accounts being used post to COPA without issues doing the regular process.

I need help from you guys to understand why this is happening, how to avoid it... Do I need to consider a GL to CO-PA config? or if there is any other COPA characteristic I need to consider to have this whole process work as expected?

Thanks!