Well, that will become much clearer then. However, I am still can't believe his reasoning on Seagull ST18 movement. It's not fragile and it works pretty well (on VCO, a few Patek, really early batch of SMP closed factory and FM). I believe there are more reps which use this movement but it's rare. Even cousinsuk has this movement for quite a high price (about 40 poundsterling).
Yes, it's thinner than ETA2824-2 or 2836-2 but this is the attribute of this movement (ETA2892-A2 is thinner too). That doesn't mean that this is a bad movement.
If you deduce from that, simply cost rather than availability that is hindering the repmakers from using this movement.