How to edit compare-at prices?

Use Case Example

John wants to make his dresses (regular size) have a compare-at price that is 30% higher across the board.

And based on the instructions we enter in 130%, but it seems to change it to 23%.

Why doesn't it match?

Formula

Use this formula on your calculator to get the right number:

The percentage to put = 1 / ( 1 - increase percentage )

In the above example: 30% = 0.3

The percentage to put = 1 / ( 1 - 0.3 ) = 1 / 0.7 = 1.4286 = 142.86%

Details Explanation

The issue here is mainly related to how we calculate the discount.
Imagine we have a product with price $100 whose compared at price is $130. The compared at price is indeed 30% higher than the actual price. However, the actual price is not 30% lower than compared price. It is actually (1 - 100/130) =  23% lower. 
Imagine we have a product that is priced at $70 whose compared at price is $100. The discount is calculated (1 - 70/100) = 30%. However, the compared at price is 100/70 = 142.86% of actual price. 
So if we set compared price 142.86% of the actual price, we can achieve the effect of 30% discount.