Wow, that's a lot of vacuum for 272's! I mean, it's probably not a bad thing, but surprised, is all. I have 264/264 in #20 and iirc, I have it ~16" (sea level), fwiw.
Just curious how are you getting the reading? Boost/vacuum gauges are decent reference, but for the heck of it, use a diagnostic or a good vacuum gauge with large dial and small increments just to see exactly what you have. Whatever the case, sounds like you fixed the issue, as 12" just seems too low for even those cams (like I said, they are not really that big to suffer such low readings).
[edit: Since they (HKS) don't give cam specs @ .050" lift (which is commonplace here to do an apples to apples comparison), but rather 1 mm, the best I could come up with on a search is the following (shown at .050"):
STOCK ...Stock Turbo Cam......174 / 165.............366"/.343"
HKS264 .......HKS 264.............187 / 186.............392"/.374"
HKS272 .......HKS 272.............195 / 195.............399"/.379"
546/547 .....Web Cams............206 / 206.............400"/.385"
How accurate that is, I'm not sure, but sounds about right if you consider 1mm (.039") lift = 218/216 deg, per HKS card:
Point is, there should be no reason to have such low vacuum using those cams, as they are even smaller than I thought. Granted, a tiny engine like our 2.0 will exhibit a bigger cam behavior with a smaller duration (for instance, even a small V8 would be considered ultra mild with those specs), but even so, I don't see why anything less than 14" or so at sea level would be acceptable, unless something else is wrong, or adjustments are out of wack. But, that's also not knowing how the cam(s) are degree'd (advanced or retarded), as that too will affect it.
Anyway, just an FYI for anybody thinking that super low vacuum is acceptable...