Mechanic w/ Cdl

Ok so I was hired into a company as a mechanic. They wanted me to get my cdl so that I could drive a tow truck for when a truck goes down. Now I have my cdl and im kind of confused about the log book situation. I was told that I would be chasing trucks within a 150 mile radius. I'm out of NW Indiana and 150 mile radius will put me into 5 different states. I work 8.5 hr shifts in the shop, I get paid hourly and I will for towing also. So my question is how would I go about filling a log book or would I even need to? I've heard that within 100 air miles and 12 hour of operation you don't need one but I'm not sure if my shop hours are included in that 12 hours...Idk I'm lost and everyone I talk to seems to be also.

 

Would having a copy of my time card keep me covered or do I need more than that? Also would my shop hours regulate me on time that I can be in the truck on a givin day? Say I work 8.5 hours off 2 hours or whatever and get called to tow. The truck is 1.5 hours away and it takes me an hour to get hooked up. Plus the trip back. All guesstimates and what ifs here lol. I just don't know if my shop time will regulate me in the truck at all