This was pointed out to me by a player and I only just now had time to verify it, but when you select a character to build off of in the character builder and it gives you a preview of their page, this information isn’t always accurate.
For example, my player played Mister Fantastic, and I told him he had Damage Reduction 5 (which he does), but when my player went into the character builder he saw that Mister Fantastic was displaying Damage Reduction -2 (which is what he had in the original print of the rulebook)
Mr. Fantastic does not have Damage Reduction 5. He has Damage Reducttion 2 from Flexible Bones 2. When he uses Body Sheet it bumps up to a 3. Modifiers to Damage Multipliers do not stack. The Damage Reduction 5 in the character sheet is an error when activating Body Sheet.
All I can say is that having Body Sheet on is intentional. It represents the state of the original sheet from Marvel which is what we treat as the default. So he might very well be spending nights as his own bedsheets.
I’ll adjust my original report on this to reflect the fact that the problem is just with the stacking.