The Is Pre-Computed toggle is for formula expressions that involve cross-object fields. It allows you to control how cross-object field values are handled during the evaluation of a formula expression. Formula expressions are typically evaluated at runtime, meaning their values are calculated when needed. However, when dealing with cross-object fields in a formula expression, the Is Pre-Computed toggle comes into play.
If the toggle is enabled, the cross-object fields used in the formula expression are computed before runtime.
If the toggle is disabled, the expression fetches the values of cross-object fields at runtime, just before evaluating the formula.
Once a formula expression is defined, you cannot change the Is Pre-Computed flag. If initially set as FALSE, you cannot change it to TRUE later.