HIs IS definitely had a very high sublevel, HA also quite some, but JS and especially DR probably not. It still took 5 weeks for him to pop in JS, which is about right. But five weeks to pop in DR, that's a bit tough. DR should be the fastest ability to train in 1 on 1, especially for forwards. This maybe means he had the lowest sublevel in DR. If all four skills (HA, DR, JS and IS) would start at sublevel 0, DR should pop almost twice fast as JS or IS with 1 on 1 training.