Thanks for your question.
Have done some research here. You define the account determination in Manage Your Solution - 'Automatic Account Determination' (in Finance Area) where you define the G/L Account to be used based on a number of settings including the 'Account Key'. The Account Key is determined based on the pricing procedure + condition type - which you configure in Manage Your Solution - Revenue Account Determination (in Sales Area).
So, if you wanted account 4400100 for both F2 (Standard Invoice) and G2 - you could simply change that in Automatic Account Determination, but if you want 4400000 in F2 and 4400100 in G2, then that's a problem because at the moment, you can't get a different pricing procedure for the Credit Memo vs. the Invoice because the two document pricing procedure types are the same and cannot be configured (SSCUI 101118). So, condition type PPR0 will give the 'ERL' Account key (by default setup) in both Credit Memo and Invoice so we can't easily change the resolved G/L account.
Some approaches/workarounds you could look into more deeply:
One approach that you can look at then is to use a different condition type in your credit memo vs. your invoice. I.e. use a custom condition type in the Credit memo (Z001 for example) - and set up the copy controls so that PPR0 from the F2 invoice gets copied into Z001. Then, in your pricing procedure, set Z001 to a different account key (ZCY for example) - and in 'Automatic Account Determination' you could set a combination on the ZCY account key to the 4400100.
(The copy control setup may require some additional research and the use of BaDI logic)
Another approach is that I understand that the field catalog for Account Determination can be adjusted. So, you can add different fields e.g. order reason or a custom field (which you could get to copy the order type for example using a BaDI) and have that determine a different account. This sounds like a bit of a simpler approach than via copy controls to me but you'd need to test the various approaches to see if any are suitable for your business scenario