I wonder if the amplifier option has been ticked?It definitely should be a single bit tick. However, it's not beyond the realms of possibility that the coder pasted in a longer chunk of hex that they thought worked which inadvertently changed another setting. I've seen this before on this forum, people recommend a long code for stuff like dipped headlights because that's what they happen to have when in reality it's a single bit change and changing more than that can have unexpected results.
I'm not saying this is what happened in this case, just that we should at least be in a position to discount the possibility given the change in audio did appear to happen straight after the coding, which is rather a coincidence!
@Wors did he backup or give you a copy of the before and after scan/coding ?