Hi Steve,
If these closers shut the doors effectively then the fire authority are obliged to accept them because they perform the required function. Just because they're a bit cheaper than over-head closers doesn't mean the fire authority can reject a perfectly good functioning door closer. I'm sure you could get gold plated door closers if you wanted to but the fire authority would be over-stepping the mark in asking for them.
The testing you mention certainly appears to be thorough, that's a lot of door opening and closing. The acid test is, do they work in situ and will they keep working for a cost effective period of time after installation? Testing over 80,000 and then 90,000 cycles is a good test of durability but you did not mention a test of duration. Testing thousands of cycles over a short period of time is different to those same cycles being performed over a couple of years with the door being wedged open and the springs held under tension for half its life.
All the fire authority want is an effective self closing door. If these closers start to fail in six months time, the fire authority will no longer be satisfied (and it doesn't matter if the fire authority know about it or not - the requirements of the FSO will not be complied with) and the closers will have to be replaced. This will be expensive. It is for the responsible person to make the decision as to whether to go for the cheaper option (testing appears good but no track record of continuing success) or the more expensive over-head closers (with a proven history of effectiveness). Another issue the responsible person will have to consider is the aesthetic appearance of the closers. He may not want bulky over-head closers over his expensive and otherwise nicely decorated doors.
I'll finish by repeating this important piece of advice - talk to the local fire and rescue service personnel. It doesn't make much difference what other FRSs have done round the country, the local FRS will be the ones enforcing the FSO in this case.
Stu