A bond is financed bail money, backed by assets as collateral...The kid probably doesn't have as many assets as the DWI person, thus the higher charge...
Better would be to find out what the court set bail at for the two...Then you are dealing with flight risk and other variables that have to be weighed to make sure they come to court...For example, if the defendant is rich, there may be a million dollar bail to make sure they show up...However, if they make a paltry 120k/year it will be much lower...The severity of the crime they are accused of is only one factor in the pricing...