Yeah but what about his other skills? As stated in the manual, skills pop faster when other skills are high.
"For the other training types, players will improve more quickly not only with additional playing time, but also a more skilled player will improve more quickly. For example, a great inside defender and rebounder will find it easier to improve his shot blocking than a poor inside defender and poor rebounder would. This encourages you to develop players with a combination of skills, but there are many combinations of skills which work well together -- you can develop players who will be a good fit for your team's needs."
So I guess there's no point benchmarking OD training for a whole season to see how fast it will pop, because it will slow down a lot as it gets further away from other guard skills such as handling, JS and passing. If all those skills are of similar level, I'm sure you'd see faster pops.