The ability for some healing spells to have an 'Overheal' effect? (explanation within)

Let me explain;

In the newer 'Wolfenstein' FPS games, there's an interesting mechanic; any Health packs you collect that pushes your current Health past its maximum still gets applied, but slowly ticks down back to its maximum over time.

In other words, if your Max Health 100 but your current Health is 98, and say you collect a Health pack that gives you 25 Health, the excess 23 Health is still added to your total, so in this case you would have 123 Health that slowly ticks back down to 100 over time, usually about a point a second? Also, your Max Health total and your Max Overhealth total can both increase, say you can get a permeant boost to those stats and lets say your Max Health can be 150 and the maximum amount you can overheal to can be 200. And of course, this pads you against extra damage.

In the context of the game it's one of the ways the game encourages the player to be proactive and progressive instead of playing it safe. I feel like Team Fortress 2 had this with one of the Medic's weapons, but I haven't played that game in a while.

However what if I wanted to do something like this in a turn based game with RPG mechanics? Is it possible to make it so that certain healing spells can apply excess HP healed to your Max HP total, but this effect decays over time (turns) until you're back to your base maximum? Is it also possible for more powerful version of a spell like this to apply more Overheal, or the player can equip an accessory to boost it?

Thank you!