I am aware of quite a few cases where there was misspelled sta"M that had previously officially passed a "computer checking".
One assumption I had of the reason to this problem was since some programs offer way too many "hearos", the person going over the computer screen gets too used to clicking "ok" that some serious issues get overlooked unfortunately. (Keep in mind, that some people consider computer checking a cheap service, therefore it is done very quickly, with alot of clicking.)
(Not a problem by the Mishmerit Stam computer system, nor by anyone that does the checking slowly and very carefully.)
I think that a possible solution to this problem, is for the program to be designed in a way that it only leaves "hearos" on the most serious problems which is the actual misspellings, and leaves out anything which is not 'way off' for the magiah who does a manual checking (Bedikas Gavra) to go over. I.e. for the programs not to leave hearos on the tzuros haosios.