Technically you do not. It is generally reasonable to assume that blank actuals on a successful run means you held to the target values without deviation. And it can save you a lot of data entry time to do so. Plus the target values will always come out in your data tables for analysis alongside the actuals.
However, this approach still rests on an assumption, and assumptions are a bad way to go for long-term data integrity. The presence of an actual value is more information than it’s absence. It’s an actual measurement or at least a positive assertion that something was done. So our recommendation is that you do record the actuals, even if they are the same as the target. Fill-down can make this easy. And in the future we will offer a “copy plan to actuals” shortcut.