I have suggestions that might help solve the problem with upkeep associated with towns, instead of lowering it at all; make sure that the town is cost effective, meaning that you only claim plots that will be owned by residents, and avoid claiming additional plots (ex. roads) that will cost the town additional upkeep. Claim and unclaim roads that lead to plots, and keep close tabs on the town bank.
Keep tabs on taxes as well; balance out the total upkeep costs with the meebles earned from resident and plot taxes to prevent the town from potentially losing money.
It takes some work to make sure that your town(s) will stay afloat (coming from the owner of two metropolis towns). You need to be willing to put in the time, effort, and money to keep a town financially stable.