Sorry to resuscitate this thread, but I cannot have this work ...
I want to do something like FieldB = FieldA * 5
So, a problem very similar to what the OP wrote.
I made sure to have my field names use only letters.
I go in the simplified field notation for FieldB, click Edit, enter "FieldA * 5" (without the quotes), then click OK ... and it returns back to the Properties pop up, with the "Value is not calculated" checked
Any chance someone can help?