Maximum HP - Heroes Feast

Does the act of raising maximum hp inherently heal you? If so, in the context of Heroes Feast, if I was at 60/80 hp and I use heroes feast and raise my maximum by 20, would I go to 80/100, and additionally heal the other 20? The wording of the spell and the segmenting of the phrasing with the comma makes it seem that after the initial max hp increase/heal, there is an additional heal. While, yes, that seems pretty hefty and a bit nuts, it is a 6th level spell that takes 1 hour 10 minutes, with a 1000+ gold requirement. Any thoughts?

Increasing your maximum HP doesn't inherently increase your current HP. That's why the very next clause in that sentence says "and it gains the same number of Hit Points".

As it happens, most common sources of max HP increase (like this spell and Aid) do also increase your current HP by the same amount, but the fact that that's explicitly stated in these effects means it doesn't happen automatically.

 Since the spell says it increases current HP by the same amount it increases max HP, it stands to reason that a character who is missing a few HP will still be missing that same amount of HP after partaking of the feast. That being said, DMing at my table I would consider the one hour it takes to consume the feast to be a short rest during which the party can spend hit dice to regain missing HP.