Rear End Gap - Sealing over Trempro 635 with Eternabond

[jami20]

I've sealed up the gap under the rub rail at the back of my trailer with Trempro 635 now. And although I'm replacing the rotten plywood at the rear with Coosa Bluewater 20 board I want to do my best to make sure it doesn't leak from the rear again. (Without having to weld or use a torch.) So, before I reattach the rub rail I'm thinking about taking some of the aluminum eternabond tape I have and putting that over the area where I caulked with the Trempro.

Is there any reason that I should not do this? I don't want to hurt the caulk job, but it seems to me the eternabond would give an extra layer of protection in the event the caulk job began to leak.