I came back to post just that very problem I encountered with the solution.
While your solution solves the tabbing around problem, there is one other problem I was not sure the answer to. What can be done in the situation where the user does in fact enter a decimal point in the textbox while entering in the amount? In that situation, the amount still gets divided by 100. ex: Enter 1500 and get 15.00(good) but enter 15.00 and then you get .15(not good)
How can the control check to see if the user adds the decimal and if not then it gets added?
I tried this(but it didn't work):
this.value=iif(substr(right(str(this.value,12,2),3),1,1)=".",this.value,this.value/100)