Another reason why mono is better for 12" dance records (another being avoiding stereo image/balance effects in clubs; and if the PA setup is mono anyway then y

Another reason why mono is better for 12" dance records (another being avoiding stereo image/balance effects in clubs; and if the PA setup is mono anyway then you'll get a real mono mix rather than a summed stereo mix.) I imagine stereo could help a bit with phase effects between speakers, but they would likely still be an issue in multi-speaker setups.