We tried the expansion last Saturday

, and were slightly confused about the handling of player assigned credits in the credit calculator spreadsheet. The amount of player assigned credits is calculated in cell M2. We assumed the intention was to distribute this in the cells N2 through R2. but if one tries to put a value in any of these cells, one gets a complaint about the cell being protected.
We unprotected the table, unlocked N2:R2, and protected the table again. After that it behaved as we would have thought.
But we felt unsure if we were doing the correct thing. If this was how it was meant to be, then why were N2:R2 not free from the start. Is this a little bug in the calculator, or did we misunderstand how it was supposed to be used?