Hi Tom,
While you are not saying it, i am assuming your are using LF-SAC.
If so, than 214.5 C temperature under the center BGA joints is insufficient 
for good soldering. By the way, time above liquidus (TAL) of 84 sec is totally 
irrelvant for assuring good soldering; you need about Liquidus+20C for 5 
seconds at that solder ball.
Less squashed balls indicate that some balls (typically in the center) did 
not melt and collapse. While I hate that SJ geometry [it gives you 2 stress 
concentration regions near the interfaces reducing reliability], proper 
'controlled collapse' is an indication of adequate wetting in the whole array.
I have no idea where P16, J12, N7, M8 are located.
Pressing on fractured SJs externally is a temporary fix [you are making 
electrical contact] which has been used for some Apple and Sony laptops (see my 
column in Global SMT & Packaging magazine, October 2007). 
Indeed, if in fact you have interfacial failures, Black Pad is one possibility
—however, you need to confirm this failure mode.

Werner



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