So if you were doing 12k hps and 4k absorbs per sec, would that be considered 16k overall?

I would hope it would be that simple to determine, but my gut tells me it isn't.

For World of Logs, it is almost that simple. Just look at the "healing by spell" tab for a discipline priest - you'll see healing+absorb=hps. It even seems to detect "overshielding", so if the priest is spamming shields that don't get used, it will not count for effective healing.

Of course you have to remember that shields are a different beast, and a disc priest might be useful for absorbs/raid cooldown even if he doesn't put out massive hps in a specific fight. But I've seen too many priests with meager healing done in random raids who say "but but disc", and I have no problem keeping up with other healers on my priest (raiding 10man with a pally and in some fights an additional holy priest), so I think you can, and maybe should, compare them.

(Kind of unrelated: the easier the fight is, the easier it is as disc to top the meters. We don't get bragging rights. :( )

interesting? with pws can cover more of raid in 10 mans and holy can only really effectively use hw sanctuary in 25 man (same with rain?) i would hardly called that surpring, but yea its interesting but its quite like for some time now..