That is kinda a normal condition with everything set at exactly "stock"(for those years around 1991-1995). We have gone to maximum CAT allowable specs in timing and seen big improvements in startup smoke.

I have even seen some go to 3 degrees advanced on pintime, but they make sure that the timing comes back in CAT's guideline of their timing curve/graph about 1000-1100 rpm and above(this is done in the timing advance unit itself). This insures that "under a pull" or "lugging the engine", that the engine is still within spec.

Note: Pintime spec is +/- 2 degrees from perfect, straight up pintime.