Sure, but not much of that battery improvement is coming from migrating the APU's process node. Moving from TSMC's 7nm process to their 6nm process is only an incremental improvement; a "half-node" shrink rather than a full-node shrink like going from their 7nm to their 5nm.

The biggest battery improvement is (almost definitely) from having a 25% larger battery (40Whr -> 50Whr), with the APU and screen changes providing individually-smaller battery life improvements than that. Hence the APU change improving efficiency "a little".