Peterson rehydrated to 147 vs Ortiz but was 155 vs Khan, Roids???

Not gonna lie I've only been closely following the sport for about 3 yrs but I've never seen this before so thought I would bring this up regarding the Peterson steroid allegations. Has anyone ever seen another fighter rehydrate 8 more lbs while staying in the same weight class within a period of 12 months? On December 2010 Khan, Ortiz, Maidana, and Pete were all 140. Ortiz balloned up to 156 on fight night and moved up to WW only a couple months later. Peterson was the lightest one on fight night only coming in at 147 lbs. Khan and Maidana were both 149 for the main event. On 12/11. Khan was the same size at 149 but now Peterson pulled an Ortiz and came in at 155. Throughout the fight he made every effort to lay on Khan in hopes of tiring him out. Ariza later admitted on FightHype that he had greatly underestimated Peterson's size advantage in the first fight and assumed Lamont and Amir were more or less the same size judging from Pete's previous fight night weight. That's why Amir has been sparring with MW and SMW training camp and trying to bulk up. Does anyone else find this sketchy or is it normal for fighters to fluctuate in fight night weight while in the same weight class?