Understanding Ppm's In The Uc System

I've been growing in UC for about 4 years now, the last 2 using CC nutes. What I've found that if you try and follow their feeding schedule exactly you will run into issues. I generally run at about half their recommended strength. When I move my clones to veg I start out using only cal/mag, Veg A&B and UC Roots. My veg system is 30 gallons so I start with 30 ml cal/mag, 20 ml A & B, 100 ml UCR. I aim for a ppm of around 180 (500 scale). This is with RO water at less than 20 ppm. For the first week or so the ppm will generally rise. Once the roots become more established it will start to drop. I generally don't mess with it unless I see the ppm rising very fast. I run this solution for the first 2 weeks or so, or until I see good growth, before changing it out and upping the ppm to around 250.

Even when the plants are at full growth I rarely get over 400 ppm. At that state CC recommends 600-650 ppm. When I've tried running that high I run into all kind of issues, both with ppm and pH, so I generally keep well below their recommendations and find my systems a more stable and generally get the desired pH rise while the ppm drops.
Same here, first grow so as a noob, went ahead and followed the CS's feeding chart... at 530-540... it was really overfeeding. I am down to 440-460 and seems to be more adequate.