When I first started cycing gear, I came off between cycles, recovered and then started on my next round. Once I went to TRT, the gains I made were not as dramatic as they were before but my weight didn't drop down as much between cycles either. Coming off between cycles, I think that weight drops a lot more than when you stay on an HRT dose. But keep in mind, this isn't all muscle we are talking about. A lot of times, guys go on cycle, then gain 15 lbs in the first 3-4 wks and they think it is all muscle. What it really is, is intra muscular water. The muscle is full and round on gear. You're in a super anabolic state, nutrients are being jammed into the muscle! Its a great feeling and with more red blood cells, you're always in a somewhat pumped state. I'm sure you know exactly what I'm talking about. Just look at a weight while you are on deca, and your biceps start to get tighter! 3 sets into chest day, and your stretching out your 2xl or 3xl shirts :) Muscle is like sponge and on gear, the sponges are soaking up the most they can. As long as you stay on HRT, you will always feel some level of this effect. When you come off, you go back to normal. At first it sucks, but then you get used to it. Over time, you get used to being normal again. Then you hit the gas once more and feel that super compensating, "holy crap" effect once more. Staying on the HRT, you never go from 0-60, so the change does not feel as dramatic. 

But anyway, thats my bro science for the day. As for your dosing, 500mg is a perfectly fine dose for deca, espeically if you are already comfortable with having done 250mg in the past. Just be aware that at 2x the dose, the chance of side effects is greater. You will want to watch out for progesterone related sides. If you find issues with sexual dysfunction, you might want to use a little caber to combat this issue, or simply reduce the deca dose. Based off your past dosing and HRT dosing, I have a feeling that this cycle will pack a little more punch and bring back some of the "holy crap" factor. Just remember that your gains are going to totally rely on hard work in the gym and supporting your cycle with the nutrition your body needs to grow. Taking more gear will not make up for a diet that is sub par. 

If you or anyone else wants to work, one on one with me on a diet plan, unique for your body and your goals, hit me up over at the Next Level Nutrition page, here at Naps Gear and I can get you started on a new plan ASAP!