I'm waiting for ITO to chime in...I know he doesn't do much service work, but the man knows retail....
Good luck attempting to go straight to the source...remember, in addition to the company that has the contract, every other National Maintenance company is courting them as well...and there are hundreds...then to sell them on calling you just for electric, just in these stores? not likely...
some companies leave the maintenance up to the individual store, then you have a good shot...but when they use a national company, it's because they don't want the headaches and hassles of dealing with individual service companies...
JJ, there are literally hundreds of companies like the one you mentioned...some are good, some are bad...we do work for a handful, but they all give a reasonable NTE...they aren't huge money makers, but they keep the men busy and some cashflow coming in...
if you had a handful of service guys, and could really manage the paperwork, you could make money...but if you are still in the field, this one will eat you up...