Se alguma função volátil for usada na planilha, o Excel calculará toda a planilha quando QUALQUER célula mudar, e não apenas aquelas com a fórmula volátil.
Para uma visão geral das funções voláteis, consulte o link
Trecho:
Excel’s Volatile Functions.
Some of Excel’s functions are obviously volatile: RAND(), NOW(), TODAY()
Others are less obviously volatile: OFFSET(), CELL(), INDIRECT(), INFO()
Some are volatile in some versions of Excel but not in others: INDEX()became non-volatile in Excel 97.
A number of functions that are documented by Microsoft as volatile do not actually seem to be volatile when tested:
INDEX(), ROWS(), COLUMNS(), AREAS()
and CELL("Filename") IS volatile although a MSKBN article says its not.