What is the DIFFERENCE in these Diagnostics?

What is the difference(s) between the 40 Minute "Full Test" Diagnostics run online on the Dell website at http://www.dell.com/support/home/us/en/19/product-support/servicetag/CQ37W52/diagnose?s=BSD and the Diagnostics run via Dell Support Assist software (10 Minute "Default" Scan & 15 Minute "Stress Scan" = Total of 25 Minutes)?

Since the Dell Support Assist Diagnostics are only 25 Minutes total, that is 15 Minutes less time (37.5% less time) than the 40 Minutes online Diagnostics.