I remember in 99 Jay was sponsored by ISS research. I think it was like that until 2001 and then muscle tech took over. Was it just cause they offered more or was there a conflict between them??
My tounge in cheek answer is because Jay knew he would never make 'mind blowing gains' unless he used 'Nitrotech' and 'Cell Tech'.
The REAL answer I found out but probably shouldn't say...
It wasnt a money issue as ISS paid him handsomely...it was about time, travel and promotion.