Would this be valid reasoning for upscaling?

[SeijiSetto]

Character A has really good heat resistance, say they can stand in lava with no effort for example.
A has previously demonstrated that they will stand still and take attacks that they know won't harm them.

Character B shoots fire at A and they choose to block it instead of tanking it, as mentioned earlier.
Would that be valid reasoning to scale B's fire above A's heat resistance?

 

[Marvel_Champion_07]

Character A has really good heat resistance, say they can stand in lava with no effort for example.
A has previously demonstrated that they will stand still and take attacks that they know won't harm them.

Character B shoots fire at A and they choose to block it instead of tanking it, as mentioned earlier.
Would that be valid reasoning to scale B's fire above A's heat resistance?

If A does that for all attacks that don't harm them, I'd say it's valid