I have a one year old Tomkat. For about 5 months I was shooting about 6 to 12 arrows every morning, and about 12 to 18 arrows every night. I'm still zeroed and it seems to be shooting very well. The problem is, with it cranked all the way, it will only reach 67lbs, not 70 lbs. I have been told I need a new string, and I have been toldI need to twist my cables. I do not have a good pro shop and have been trusting the guys at sportsmans warehouse. Any reccomendations?