I would do the trade.
That value chart is fool's gold this year since this is such a deep draft and the 3rd round pick should have more value than what the chart reads, so a pick at the top of the third round for a drop of 10 slots is MORE than worth it.
Iupati looks great and will surely make some team very happy, but the fact remains: we need a pass rush, we need DEs and OLBs, we need WRs, and we need an ILB.
If the Patriots somehow landed Karlos Dansby, this would open up the draft and allow Belichick the luxury of taking a guy like Iupati, because then he could focus his other picks on needs, but given the current needs, I don't think you can take a guard in the first round. Too many holes to fill more important than guard.
In 2007 Koppen, mankins and Light went to the Pro Bowl, and it wasn't because they used to be so much better than they are now. It's because Brady had more weapons and got the ball out sooner. Just like a pass rush makes CBs look 10x better, WRs make the offensive line look 10x better.