i know what you mean qwety and bongrips. I believe I have the answer u desire:

I was questioning why some highs hit very intensely, while some slowly rise. and it hit me that when I use a bong I typically have a more intense rise. now what is the reason for this, the size of the hit. the larger the hit the more sudden it will come on. lets say it takes 3 minutes for the peak of a hit to arise. if u take 2 huge ass hits in a row, u will be peaking very intensely, but lets say u smoke a little hit and then 10 minutes later hit another, u will just spread the peak out into a weaker peak.

So the reason is partially due to dose, but also how quickly u finish. If u smoke a joint alone it may be very very intense due to the fact that it is hit after hit after hit, with maybe a little oxygen. so that is why.