Sure, I can think of a few complicating factors. First, on the negative cash flow side of renting, you would be on the hook for property taxes, insurance, HOA (if applicable), and some utilities.
Second, on the positive side for renting (but not easily fitting into the cash flow category), your equity would grow as the tenants pay your mortgage. Consult your amortization table to see exactly how much of a boost that is per month, but it should be appreciable. Also something to consider: depreciation of your rental house could have big tax advantages--essentially a low interest loan from Uncle Sam.
Third, a toss up: holding on to the property means its value for when you do eventually sell it could go up or could go down. A difference of 20k over a few years is plausible and would skew your calculations. But who knows what will happen?
Lastly, renting is a pain in the neck. I don't know your circumstances, but $2500 seems less than automatic. A lot of people are priced out near that point or prefer a 3 br, etc. Also, plenty of paper work, effort to find tenants, broken water heaters, noise complaints, and other non-autopilot stuff.
Bottom line, there's plenty to consider beyond immediate monthly cash flow. Renting is likely to be a lower cash flow option in the near term factoring in the various upkeep costs, but could see some larger lump sum gains later on.