You will rarely ever see, especially as a homebrew high level of dms from 2-row, basically never. Couple reasons people would suggest a 90min boil, DMS, Hop Utilization, sterilization, wort concentration, color can be effected, PH and various compound effects. Here is a nice summary or points towards boiling below. There are too many factors on what you are trying to achieve to give you an idea on what your proper boil time should be for each beer but 99% homebrewers are fine at 60min as long as they avoid large amounts of malt with S-Methyl Methionine (produces DMS) and are getting proper sterilization.
Killing spoilage micro-organisms.
• Reducing the amount of coagulable
nitrogen thus promoting colloidal stability.
• Extracting the desirable principles of hops
to give beer its characteristic aroma and
• Reducing undesirable volatile compounds