I'd guess you have a later revision (service manual is AWR-030-0), which seems to be the case since your board is marked AWR-030-A. When recapping my 8100 I did notice that a number of the boards were redesigned in later revisions and thus did not match up with the service manual. A good example is the protection board. I have AWM-027-A, which matches the service manual, but it was redesigned later, and the layout is not the same and does not have the same components. I recommend making sure each of your boards matches up with the service manual board layouts/parts list.
I am not expert enough to agree or disagree with whether you can sub a 330µF/35V cap for a 220µF/50V on that board, though the lower voltage of the 330 cap from the 50V cap you have in there would raise a red flag for me in addition to the significant difference in capacitance. My understanding is you can go higher in voltage with replacement caps, but not lower, and you need to match capacitance, so that is what I follow when doing recaps.