and there is a decent chance it will drop by the maximum 25%.
Are you sure the maximum is 25%? I thought the new difficulty can't fall below 25% of the previous, since the current diff is 19.9T, the lowest it can go to would be 4.97T, but nothing stops it from going down 25% or 50%, correct me if I am wrong.
I am not sure I am understanding what you are asking.
Each difficulty period, the difficulty cannot change by more than a factor of 4. This means the difficulty cannot increase by more than 400%, nor drop by more than 25% from one difficulty period to the next. This means that if it took five weeks to find 2016 blocks, the difficulty would only drop by 25%. All else being equal, if this were to happen, it would take about 3.75 weeks to find the next 2016 blocks, so the difficulty would decrease by an additional 25% at the end of the following difficulty period.