Is there a pattern on how much stats does each enhancement scroll give?

From what I heard there is a chart that gives a certain amount of weapon attack per enhancement based on the amount of weapon attack there is.

1-49: +1
50-99: +2
100-149: +3
150-199: +4
200-249: +5
etc

However, I haven't found sources confirming about + stats though.

Is there a pattern for +stats as well?

Also, does this pattern chart only work for weapons or can armour get them too?

For example I have a Red Belly Duke (100 Pirate Overall) and it has been scrolled 12 times using Pinnacle +9 stat scrolls making it +108 stats fully scrolled pre-enhanced. How much stats would there be after 15 enhancements?