Why do hanafis pray fajr congregation at a later time outside ramadan and pray early in ramadan

I have seen many times the congregation time for fajr on 29th Shabaan is 5:40 AM and 1st Ramadan its 5:10/15 AM. Similarly the time for 29th Ramadan 5:00 AM and 1st Shawwal 5:20 AM. Other days the time difference from day to day relative to sun is only 5 minutes. But when ramadan comes they pray early. Azaan times also change like congregation time in Ramadaan. Do they have something specific to pray early in ramadan or has abu hanifah given any instructions to do that? Doesnt this amount to hypocrisy in applying different rules to suit your ease?