skyguy1983

The UDP will not cover the upcharge items in the MDR.  If you eat in the MDR and want the filet or lobster, you will have to pay the upcharge.
The only down side to having the UDP on a smaller ship like Enchantment is that you will end up eating in the same specialty restaurant numerous times.  If you want true variety, I would recommend you stick with the MDR and just pay the upcharge if you want one of the upcharge items.  If you want a filet or lobster every single night then you should stick with the UDP.
If I understand your OP correctly, you have paid $590 for 5 UDP packages.  $590 will buy a lot of upcharge items from the MDR.  Personally, I think your best bet would be to cancel the UDP, go to the MDR and order the occasional filet or lobster if the mood strikes.  As a frequent user of the UDP I can attest that you do get tired of eating at the same few restaurants after a while....especially when you throw in lunches on embarkation and sea days.

The UDP does not cover the upcharge menu items in the dining room.  For Enchantment effectively purchasing the UDP means you can eat in Chops whenever they are open (subject to seating availability).  I'm not sure the UDP has much value on Enchantment as the only option seems to be Chops.

Eating in the MDR alllows you to order lobster or a nice steak with an upcharge.  The environment is totally different from the specialty restaurants.   We like the MDR and don't want to pay extra $$ for specialty restaurants, but others want the less-busy atmosphere of the specialties.   I'd say you got a good price on the UDP, and you could always try it this cruise and then do the MDR another time.  Some travel agencies will give you specialty dinner or lunch coupons for an upgraded stateroom (e.g., balcony), which is what we do when we want to experiment.  Overall, there are advantages to each so it is a matter of $$ and your preferences for dining.  I'll let others who have used the UDP explain their strategies....