Go ahead and switch.
If you want the Premium stuff, go with the Redline 15w-40. It's a mere $30 a gallon! But it's great stuff. i am switching back.
Redline probably is the best High-temp oil because it uses ester base stocks, not PAO. that's also why it's so $$.
Don't expect to save money on the Redline, no matter how far you extend drains. it's not an investment. It's a luxury.
Justin