Ignore entered cell if not tabbed off it

I have a scoreboard where I have a button to correct the last score entered. Say for example I enter:

A1 = 100
B1 = 100

Then I click the correct score button, it deletes B1, changes it to blank, and leaves the cursor there to re-enter correctly.

However, if I click the correct score button, before tabbing off B1 (i.e. I enter 100 in B1, don't tab or press enter, and click the correct score button), then A1 is cleared, and B1 remains.

Is there any way that in this instance, B1 goes blank along with A1, or is the order of events and position of cursor going to make this too complicated?

Happy to elaborate if the above doesn't make sense and appreciate any help