Issue is on: https://www.roblox.com/develop?Page=ads
i = Impressions
s = Estimated sitewide impressions
a = New ad value
t = Total ad value
The formula used appears to be:
i = sa/t
The correct formula is:
i = sa/(t+a)
The current formula is linear as a increases. It does not take diminishing returns into account, which is crucially important when your ad spending is a decent chunk of the entire sitewide ad spending.
The correct formula is asymptotic.
This isn’t necessarily a mistake though, it may be to hide information.
The value of s/t can be derived from the current formula, but s and t individually cannot be calculated.
The correct formula allowed both s and t to be derived.