Didn't see the prog settings...
I would venture to guess that the park has been "cherry picked" for higher-conducting signals - if Texas is anything like Tennessee then nickels will be found in great abundance in most places! Since they are so conductively simliar to aluminum trash a lot of people don't have the patience or time to sift through VDIs to get nickels - and probably want better bragging rights if running a program that discrimninates out everything at a zincoln and below...at times I have been one of those people!
But with the Deus - like you said before - it's a little different. The sheer versatility of this machine makes it possible to hunt whatever you want at the time; whether it be silver dimes or better -OR- nickels only on another day. When I used my CZ detector a few years ago and went hunting older schools I almost always found a TON of nickels while some tabs and beavertails came through. That machine would really pick through the Al trash for nickels - better than anything else I used before!!! I didn't mind, and still don't mind digging a lot of trash most of the time unless I'm at an old homesite where time is a factor. I remember that finding silver used to be a hootin-an-hollerin event for me since it was so rare. But I was competing with most likely a BUNCH of cherrypickers...
The biggest difference I see with the Deus over other detectors (and this is just my observation) is that it can find smaller non-ferrous items DEEPER, mixed with, and/or under iron targets. I know this is what the Deus was designed for...but observing this trait in the field really gives me confidence that if I get my coil over a coin 8" deep or less, on "2" reactivity - then chances are almost 100% I will get it. The more I use this detector, the more SMALLER items I am seeing at depth. This is why, in my opinion, the Deus is such a great machine!
Recently I've been meandering (no gridding or systematic hunting) through the old fairgrounds site close to home and have been pulling 1-3 silvers every time, and at least 1 Wheat...each hunt ranges from 2-4hours each. Relics have been found here -so I don't notch anything except 1-10 and 97-00. I get a lot of tabs, but overall there is a big variance in what you CAN find there - ranging from 7" deep zincolns to 2" deep silver quarters. It's 30 acres of chaos but the finds keep on coming!