few reasons why they may have done this:
Firstly they could do the MOT first as then they could profit or accomodate any work that may have come up as a result as this would give them time to get any required parts etc.
Secondly they would look silly if they did a service then it failed the MOT afterwards... (although lets face it, a service doesnt actually include alot).
Thirdly, logistics..
Lets say they have an MOT bay, and a few service bays. They have a fairly full day and can only service or MOT so many cars at a time. It could be two cars are being serviced and the other is sitting there doing nothing. The MOT bay could be overly busy later on, or perhaps people may call in wanting an MOT. So it would make sense to be MOT first thing so that there isnt a rush later on as they can only process so many per hour..
Fourth: the MOT check could pretty much bdouble up as the inspection part of the service, then if nothing is found they simply do the lubrication filter changes and voila all done in record time.
Fifth, perhaps the MOT bay is not busy first thing, they may find people turn up for MOTs later on and so doing yours when bay is empty frees up capacity later for urgent MOTs.
and finally, lets face it, many members of the public dont know about cars, it is possible that it could have been something else, so actually they are being thorough confirming its the spring before doing the work. Imagine they had changed the spring and then called to say it was actually something else.
So, on the face of it they have been silly, but actually perhaps not. - Dont forget the retest is just for the affected part. They would likely just take a look under the arch and see its been changed. a few seconds.
