Looks like the python scripting functions (for e.g. mean, max..etc) don't consider the quality status (good or bad) of the tag for calculations. They only do justice to tags with good quality. Only way I think is to write scripts to check for quality of tags and perform functions. Is there any other way out?
Well it's not too hard nor too long to do something like this:
values_expr = (qval.value for qval in your_tags if qval.quality.good) return sum(values_expr)
Every tag read system function delivers a
QualifiedValue object for you to inspect. Many scripts just take the
.value of it immediately, but you aren't required to do so. Inspect each
.quality as you wish.