Currently (version 1.3.0) there is no reason to have decks 11+, as there is no way to assign a separate waiting time before next learning for decks 10+; they all use the same delay before expiring. I would suggest one of the following changes to the program (in order of my personal preference). If there is enough time, I would suggest all three changes be implemented.
1. Add the abilility to assign unique delay for decks 11-20 (at least).
2. Make the deck with the highest unique delay time be the highest deck. For example, if the delay can only be assigned for decks 10+, then make deck 10 be the highest deck. I card in deck ten that is tested and passed would remain in deck 10, but the delay counter would be reset.
3. Provide the ability to assign a deck to a particular card. Currently, the user can reset a card to the Start Deck. I would suggest replacing this with a function to assign the deck based on user input. This would be a useful feature in general, but it would also allow users to reset all cards in high decks to the highest meaningful deck (in terms of delay, currently deck 10), assuming my second suggestion is not implemented.
I love this program, and use it daily. Thanks much for all your hard work putting it together. It's taken over 2 years of me using the program regularly to notice any features that I think could be improved, so it is obviously a very robust program. Thanks again!