It's a bad idea to have 10 SSIDs. Each SSID (hidden or not) will eat into your airtime and slow down everything, especially on 2.4Ghz. Reduce your SSIDs.
Either way, turning off the 5Ghz radio won't increase the number of SSIDs available on 2.4Ghz.
What are you trying to achieve exactly? Why so many SSIDs?