This level of testing finds most errors at a low level. Higher level problems require application testing. Our programmers will test most application functionality during development as well. This is the most efficient point to find and repair errors. But final application testing should not be done by a programmer .
Programmers tend to overlook simple errors like spelling and grammar.
Programmers have looked at that form for hours. They have made sure that everything works. They don't test for the unexpected. Our quality control team is made up of support and documentation staff. They 'enjoy' finding problems with software and see that they get fixed.