About 4 years ago I replaced a compressor unit. I did not replace the air handler in the attic. Now is a good time to replace the air handler (new roof being put on). The compressor is 10 SEER rating. As of January 2006 all air handlers have 13 (or better) SEER rating. Is it OK to mix 13+ SEER air handler with 10 SEER compressor?[?]