Sounds a bit far fetched to me cfimei. Where did you see this?
My 737 TR provider ran sim sessions in 4 hour blocks, with two hours PF and the other two PM/PNF. If an organisation is offering '24 hour' ratings then something is wrong. Bearing in mind you need 4 hours for the LST at the end of the course, that would leave you with 5 sessions or 20 hours to get to the required standard. As for it being realistic for someone with no prior jet experience, put it this way - my sim partner on the 737 TR had a jet command on another type and had in excess of 11,000 hours. He commented he felt he needed all the hours that were available on the course to get to LST standard. My course allowed for 40 hours prior to the LST, with additional hours programmed in if required. I don't know the ins and outs of the course you mention, but from the info you have provided it sounds at best an optomistic view of the hours required to get a TR on any jet!
I should add that i went to a JAA approved TRTO provider, and it was UK based.