Yes that's it, the beginning of his training is amazing but when it works it's all benefit like you said.
I still believe he enjoyed very favorable conditions!
When he arrived at 18, he had 6 IS - 6 ID - 7 RB - 6 BL, To jump up to 11 ID, he needed at least 12 weeks in optimal conditions with a very prolific first week in pops, but it could well have taken up to 16/17 weeks.
After reaching this level of ID, his training is more classic and above all very logical.
I think he was a Lucky guy!