Wow, this is a good thread.
Alpha, I've run almost this exact same cycle (little less test and ran the dbol for 6 weeks) and I put on 20lbs (kept about 75% over the next 6 months). Deca is a bitch to come off of. Takes forever. The way I like to do it is I run the test for 2 more weeks than the Deca just because it talkes so long to break down. Then I wait 2 weeks and then start a 4 week PCT with Nolvadex and HCG (this one is pretty important with deca, I didn't use it the first time I ran deca and my PCT didnt completely recover me so I was not myself for a couple months). I've also found taking tribulus in my PCT to be helpfull for me but thats just my own experimentation and I've never read anything for or against it.
I don't recall not making gains after stopping the dbol. But if it was your 4th week you might consider that your body gets tired of training straight after about the 4th or 5th week. Theres a really good thread on this phenomenon here:
http://forums.steroid.com/showthread.php?t=145655
so it might be that your body is a little tired. It could also be that your water retention dropped slightly while you made gains so it looked like you stayed even.
In any case, this cycle is the bread and butter and I effin love it. I'll run it again next winter with some Abombs. Good luck and post some before and after pics when you finish!