A ringtone in OTA-format isn't 1 to 1 with RTTTL-format, which can be found on the net. For example in RTTTL you can't have loops in side a ringtone, which is possible in OTA.
Multible patterns are used so that one ringtone can have variation inside it, and also save space. For example first the ringtone starts by playing part A then playing part B and looping twice and then play part C and loop three time. Or some other kind of variation.