GReddy Turbo-Timer...keeps changing after-shut off run times on its own! ARRGHHH

I can't figure out my GReddy turbo timer, and curse me for not being Japanese. No instructions in English, how helpful! This is the deal:

Yesterday, I drove the car for 30 miles. The timer ran the car for 9min 50 seconds after I pulled the plug. Today, I drove the same distance again...drove it the same style, same speed, same distance...but the timer only ran the car for 1.5 minutes ... what gives? Is there a way I can set it to a fixed time? Or does it somehoe "calculate" according to the driving done how long to keep the car running for??

Don't quote me, but I'm almost positive that HOW you drive it (how long you are under boost) depends on how long it goes. Like I said, I'm not absolutely sure about this, but it makes perfect sense! :)

yeah there is a way there are 4 different settings two of them are preset and those u can set for up to a minute and 30 seconds and those are givin to how high ur rpms go when driving but allways shut off no matter how long its driven for and the other two are the ones that u set but u havent set them so it judges on its own and sometimes the little chip in there isnt the best at guessing i had the same problem try switching to acc mode if that doesnt work