I'm not exceptionally familiar with the 6G74, but am very familiar with its cousin the 6G72, both SOHC 12V and DOHC 24V.
I think its possible you may be a little confused on the instructions. Usually the purpose of putting the crank back 3 teeth is to move the cam gears into place without the valves making contact with the pistons, but it should be at TDC when the timing belt is installed.
On the 24V DOHC and even the 4G63 the once the cam gears are aligned you usually put the crank gear back one tooth from TDC before installing the belt because the hydraulic tensioner will pull the crank gear forward that one tooth keeping everything aligned.
When it is all installed you should rotate the crank the proper amount of times and all marks should be aligned at TDC. If the crank is 3 teeth back from TDC the vehicle will not run, or if it does it will run poorly. I hope for your sake that I am misunderstanding you and you didn't bend valves by having the crank at 3 teeth BTDC.
Lastly the purpose of the "60k service" is more than just replacing a timing belt. Very few people have ever broken a timing belt. The vast majority of those that have broke it only because another part of the timing belt system failed and burned the belt up. Thats why those other parts of the timing system (water pump, tensioner, idler(s), etc) are vital to be changed with the timing belt.