I just installed the TST 507 series and they set it up for me... I run my tires at 115 psi... the low is set to 103 psi ( 10%) and the high is set to 144 ( 25% ) ..
They told me the standard was 10% for the low and 20-25% for the high setting
I just ran from PA to Richmond VA which was around 300 miles... 1st half was rain and mid 60's.. the psi was 120-122 psi... the 2nd half was sunny and mid 70's... the psi was 138-140... I am curious to see what they show when running in 100 degree heat down south......