Simple Upgrade Question (Base vs Increment)

This is actually a simple question. Example:

An Upgrade (Of five (5) levels) has an Effect 1 for Movement Speed Bonus (%)

I wish that for every level researched for this Upgrade, the speed bonus would increase by 5%.

My question is what's the difference between Base and Increment; what values would I enter if I wanted to accomplish an increase of 5% per level.

Thank you ahead of time, help is appericated.