Cant speak for others but IMO it is very difficult to bid something without seeing it, particularly snow or lawns. Square footage dont mean squat as there are so many varibles to consider. EX: Are there parking lot islands, where can the snow be piled, what are the properties hours of operations, is it always open or do the cars clear out after 5 pm, is there a big empty field next too it that will dump all the drifting snow into your lot, just to name a few.
Please understand Im not looking for you to go through and answer these questions because those few examples still arent going to be able to answer all the questions I'd have.
Its kinda like calling up the Doctor on the phone and telling him you've got a pain your side. He sure as heck isnt going to prescribe you something based on your opinion or best guess, hes gonna wanna see you.
Everyone on here is very helpful about many things but getting down to specifics of you situation is a difficult call, particularly when you consider all the different sizes of companies and their specific overheads and methods of operations.