If date is less than in cell, change to the next formula, if not, stay on the current formula.

[DailyCaffeine]

I need the formula to change depending on what value a cell has

For example, if B2 < B15, the formula changes so that the cells it's using in the formula goes down by one, if not continue using the formula.
However, once it changes, it will keep that new formula until the date becomes less than B3. So on and so forth.

I can figure out the first part but I am not sure how to do the second part.

Thank you in advance if you can help

 

[vladimiratanasiu]

I need the formula to change depending on what value a cell has

For example, if B2 < B15, the formula changes so that the cells it's using in the formula goes down by one, if not continue using the formula.
However, once it changes, it will keep that new formula until the date becomes less than B3. So on and so forth.

I can figure out the first part but I am not sure how to do the second part.

Thank you in advance if you can help

Your message is unclear. Post it doubled by concrete examples, designed as editable tables (not as images) with initial data, formulas and final desired results.