Well a unit will be for 68k, but when you buy in large qty. ofcourse it won't price you that much, but still costly enough.
Shri Screambowl ji to Raytheon execs - "Bhaiya theek theek laga lo... 2000 lene hain". Next will you suggest an all cash transaction to avoid sales tax?
My assessment is Pakistan has acquired/stolen Ex-Cal rounds from US which was leftover in Afghanistan. You think they did not? I can't prove it but to me it makes sense that they have at least tried to get it who knows they have or not. May be MI knows. In late 80's Pakistan had got stinger missiles from the leftover which they used in Kargil to down two of IAF aircrafts one was heli. India for 8 years was unaware of this fact, till some of those missiles were destroyed by the ISI.
The stingers were handed over to the Afghans and made their way to Pak. That is not the case with Excalibur. Or you think Pakistan made some mission impossible like heist at Bagram Airbase?