"Now, that study (NRC 1997) finds that the lifetime fiscal impact (State & local + federal) of immigrants with less than a HS (high school) education is -$89K," . For the third time we are not talking about immigrants decendents we are talking about how much immigration "has" and is costing the U.S. Taxpayer,. Figuring in decendants,it would take 18-20 years to see any positive. You are also assuming that each and every immigrants decendant will graduate form high school and not join a gang or add to the crime rate in any way. You also do not take into account the new immigrants that are entering our country every day. The career criminals, the rapists, murders, thieves, gang members, etc. Again, so far you have only proved one small segment of the immigrant population that is capable of providing a positive contribution.
You also do not take into account job displacement or job devalueing for native U.S. citizens.