Ok, the underlying problem was that the ProdID was not being entered and is required in the subform. I re-checked the AfterUpdate event and your original statement, using the bang operator does work.
In my haste to offer a solution, I changed the bang operator to the dot notation, spent some time working out your subform and underlying tables and got it to work, even accounting for all the labels in a foreign language. I failed to mention the ProdID aspect, sorry.