Yes, the absence of coolant in your oil analysis is great news! So, what brand and viscosity oil have you been using? Seems the first sample maybe didn't give the lab as much volume as they could use to do all the testing they needed, first go round. Were you short on oil to send out? This first sample analysis serves as your baseline for continued oil analysis throughout the life of your tractor's engine. The second sample should give a better picture of what damage, if any resulted from the engine block heater having blown out of your block. Hopefully you will have gotten lucky and the results could continue to show minimal to near non-existent harm. I'm hoping that is what is found, and you will be good to go forward. I would caution to keep a close eye on the block heater too to make sure there are no signs of leaks or outward movement of the bushing/heater assembly. Good luck with this and please give us your next report when it comes in.