are some torque settings in the superdream manuals right

hi im in the process of rebuilding yet another 400 n superdream yes i am addicted to them , i got the engine stripped put new crank shells in big and main , put new camchain in the balance chain still had ages to go gasketed the crankcase and sealed it up done up all the 6mm bolts 8 - 12 nm which transfered from the manuals are in 1.0-1.4 kgm . the one that caused a lot of problems though was the big 8mm x 135 mm bolt at the back by the final drive sprocket , did this up like the manual says to 2.0 - 3.0 kgm i didnt have to transfer this time as i have a different torque wrench wich covers thissetting , as i got past 2.0 i knew i was getting to close to disaster lo and be hold it snapped . once again i took the crankcase apart and thankfully there was enougth of a bolt left to use monkey grips on to bring it out . i thought at first it was a defective bolt because the thread hadnt stripped ii cleaned it up again sealed it and closed it . once more i put the bolts in and did them up got to the last one unfortunately the big old 8mm again got nowhere near 3.0 kgm it snapped i couldunt believe it .before i got to despondent i opened it up to see the damage once again it had left just enougth for me to get the remains of it out myself . the 3rd attempt again i cleaned it sealed it and also cleaned all the bolt threads with a proffesional die . i once again sailed through the 6mm bolts , and then it came to the 8mm i got it fairly easy to 2.0 kgm then the bolt began to creak as i turned it i lost my nerve when i goto 2.5 . have any other members had problems doing up this bolt i notice at the beginning of both manuals it stipulates 8mm bolts should be done up to a torque setting of 1.8-2.5 . i notice the haynes manual also reads just like the honda at the front 1.8-2.5 in the crankcase rebuild section 2.0-3.0 . also i have found a problem doing up the flywheel bolt in the manuals it says a ludicrous setting of 10-12 kgm i have the proper flywheel holder and could only keep hold of both the flywheel and torque wrench to do a meagre 5.0 setting ye t this never came undone even when doing over 90 mph  . at the front of the manuals it says 10mm bolts should be done up to 3.0-4.0kgm thats a difference of a massive 7.0 kgm just because its on a flywheel . please can other members give their thoughts on this matter paticuarly honda mechanics and technicians thanks for reading keep it in the redzone