User blog comment:FairyRaven/Fairy Tail Chapter 427: Pitched Underground Battle, Review and Commentary/@comment-76.121.234.236-20150406132532/@comment-1359322-20150406133550

Think again. The FT members who were sealed for 7 years, were able to catch up to those 7 years later with just 3 months training. Natsu had 1 year fully dedicated to training plus he has his second origin unlocked by Ultear. This is quite normal. At least this is way more believable over the 3 months training covering 7 years gap of strength.