If you are proposing a wide aisle facility, it's not wise to specify a floor flatness specification that requires measuring along a defined wheel track path, even if you plan to change to narrow aisle in the future. Firstly, the change often doesn't happen. Demands change, how are you going to second-guess where you truck path is going to be in the future? And are you really going to move all those sprinklers, lights and racks? Even if you did measure the floor and made the contractor do minor grinding where it was out of tolerance, this does not automatically mean the floor will be in tolerance where the trucks actually run - in either wide or narrow aisle configuration. Besides, with a tighter tolerance there will be more joints. You may cleverly locate them under today's racking, but you'll be pretty smart to also get them under some future racking system. The less joints there are the better. Less joints mean less maintenance.

I'd go for a Concrete Society TR34 FM2 specification. Don't be fooled by names. Just because a floor is specified as Category two or FM2, and is not therefore described as 'Superflat', does not mean it will be an inferior floor. In terms of finish it may be better. A lot of work has to be done to the top of the wet concrete using highway straight edges to get a 'Superflat' floor, and this sometimes detracts from the finish. It is certainly really tough to get a coloured dry shake floor to Superflat tolerances, and grinding such a floor makes a mess. If you don't need it, don't specify it. Spend your money elsewhere in the floor, perhaps by armouring trafficked joints, or specifying a light reflective slab to save energy on lighting - that helps us all.