My bad. It looks like both classic and professional have the same 10-30-20 formula. I thought it was different because Jack's sells a hydroponic formula called Jack's professional hydroponics, and that's not classic.
I can't see any problems using their 10-30-20 bloom booster in coco as long as you supplement with calcium nitrate (which you're doing with cal-mag) or use limestone (can't flush this, so decide once) in the coco.
The only issue there could be is that hydroponic formulas should be low in ammonia and urea forms of nitrogen, and high in nitrate nitrogen. With coco, you get some leeway on this, but in DWC, you really don't want urea. Hydroponic formulas should get the majority of their nitrogen from calcium nitrate and potassium nitrate.