The difficulty with 5e escalating HP and Damage.

Working with 5e we came across a difficulty in just multiplying x5 for damage and HP.

In 5e, it uses escalating hit points per level unlike some of the other game systems. A hit die is added. Different sided dice are used to represent characters having different life force values. There are four, six, eight, ten, and twelve sided dice.

In trying to multiply by five, this is what happens each level.

Four sided dice becomes twenty sided dice. Which I figured could be two ten sided dice.
Six sided dice becomes thirty sided dice. Which I figured could be three ten sided dice.
Eight sided dice becomes forty sided dice. Which I figured could be four ten sided dice.
Ten sided dice becomes fifty sided dice. Which I figured could be five ten sided dice.
Twelve sided dice becomes sixty sided dice. Which I figured could be six ten sided dice.

On paper and at first this looks okay. Just add that amount is added at each level.

From one to twenty or 60 points of life each level.

By level two it's two to 120.
By level three it's three to 180.
...

But the amount of dice becomes clunky rather quickly.

We tried implemented a d100 once 10d10 was reached.

This created numbers like 8d100 + 4d10 + 58 or something like that.

That was fine on paper. After a day of him working on monsters, I asked Peter if he could figure any other way to smooth the amounts out. He suggested just maintaining the original system.

Looking at the other D100, Runequest uses such a system for their system. Rolemaster, although chart based has numbers. But both of those systems don't have automatic HP increasing each level like 5e and other editions - more unique to it. So they don't create the problem of escalating hit points, which creates clunky dice rolling.

So after reviewing that system I agreed that we should maintain the original hit point and damage system, and try to adjust the bonuses to maintain a separate skills/saving through d100 and the HP & damage using the different original dice, hit dice, damage, and hit points.