In the past 5 months I have acquired two sets of Rotosounds and I have had trouble intonating both sets. This applies only to the E string, both sets have been too flat. One set were the nylon wrapped strings, which I though may be to the extra length of my Artcore (total string length requirement, not scale length). However yesterday I tried a set of Jazz 66 on my Bongo and the E was flat even with a maxed out saddle. Anyone lese have this problem? Should I contact the company?