My first step would be to contact the management company and confirm the maintenance and what it includes. There may be appliance surcharges included in your unit such as a dishwasher, or air conditioners that might not be in the upper floor apartment. If your unit was being sublet by the prior owner he or she may have been paying a sublet surcharge on top of the normal maintenance which is common in some buildings.
Also, not all one bedrooms are equal. Check the square footage from the offering plan because it's possible the other unit's configuration is different, or it could be smaller, thus, the lower maintenance. So you need to sort out these details before going to contract. Hope this is helpful to you.
Bonnie & David