The South Yorkshire-based outfit were accepted for the 2010 season along with USF1 and Campos, but have subsequently seen the future of the sport plunged into doubt due to infighting between the governing FIA and Formula One Teams Association.
Having entered with the original £40 million budget cap plan in mind, the recent changes in the sport could leave them with vastly-inflated running costs if they are to compete.
"Every time you think you've got it sorted out it all changes again - it's like walking on quicksand," he told Autosport.
"But until we see what the Concorde agreement is - if they ever sign it - then we'll comment.
"It (the lack of a cap) makes it more difficult of course, but I think we can just about manage it. It just depends what the target is in two years' time.
"I can't really comment on the agreement until I know what it is - it (the recent announcement) was very broad, wasn't it?"
Booth said he probably would not have entered a team in the championship under 2009 rules.
"Probably not," he replied when asked the question. "But are they sticking to the 2009 rules? No refuelling is quite important.
"Until we see the exact rules, all of us are just guessing."