I have a Hot Rod Deluxe. Recently, I put in a pair of Sino KT66 tubes and biased them at the bias test point at around 62 mA for the pair. I just received a pair of Groove Tube KT66HPs and put those in. With the trim pot in the middle (around where I was for the other pair), the HPs are reading 120 mA! In fact, the coldest I can get them is around 87 mA for the pair. What's going on here?