I have 2 new HEAD MG Radical Pro rackets I have bought recently. Same grip size. 1. Strung with Head Sonic PRO 17, rubber band - 11.75 oz 2. Strung with SPPP 17, rubber band - 12.05 oz The second one is noticeably heftier (I wonder if balance is different too). So, by my calculations the difference is ~2.5% Is this considered to be acceptable by racket manufacturers? I don't suppose that different strings would give such a big difference in weight... Thoughts?