I am setting up a spreadsheet to calculate interest on a loan amount. The
interest rate, while somewhat stable, does change (more often than not
nowadays!). At present, the current interets rate is entered into a protected
cell at the top of the page. Then, the sheet will recognize if a transaction
process (listed in column A) is an "Interest Calculation" (rather than a
debit or a credit). If so, then, the current interest rate (obtained from the
input cell) is placed in column J and once a date has been entered (column
B), the interest on the daily balance will be calculated.

PROBLEM is, when I change the interest rate, then all the previous IRs
change to the new value. This is because, I have basically used a formula
(copied in all cells of column J) that, once it recognizes that "Interest
Calculation" is the process (in Column A), it simply retrieves the current
interest rate from the input cell i.e., =IF(A22="Interest Calculation",J$13,"
").

I need a way to "fix" the IR once it has been "loaded" into the calculation
rows of the spreadsheet.