Local taxes

This is the first time I have ever ran across this, but the current city I work in is 1.5% and the municipality I live in is 1% but they only allow a credit of .5% of the 1% liability.  Is this legal?  I would understand if I moved to a community that was 2% and only had 1.5% that I make up the .5% but never heard of only giving a partial of the local as credit.