Yes, that does sound like a really low RMR, because BMR would be even lower.
But that's compared to expected based on age, weight, height.

But based on bodyfat % where you may have burned off decent amount of muscle mass through dieting, it may be sadly right on.

That does mean a TDEE based on age, weight, height, as you've probably done - is inflated.

If your BMR really is lower because of higher BF%, you eating more than really needed will never correct for that, until you slowly gain muscle back. And eating in surplus (which you would be) and lifting weights hard, could give you maybe a lb every 6-8 weeks.

So you might want to confirm you are starting your math with best estimate of BMR, potential BMR, not a suppressed RMR either, based on good estimate of BF%.
Then get TDEE from that and work your way up to potential TDEE from current eating levels.

Spreadsheet on my profile page can help with all that. Stick on the Simple Setup tab.
There is a field to enter your tested RMR, but it'll probably warn you it's 5% below potential so don't use it - so don't.
No need chasing a suppressed metabolism in to the ground more.

And yes, this method can greatly improve this.

And you likely have no idea on your energy level, unless you had something to compare it to.

And you'll need more than a few weeks, you'll need minimum month, but likely 3 months to see any improvement to RMR. You'll likely gain some needed water weight first off.
Hence advice to increase slowly to best estimated TDEE.

I guess that's good the TDEE is higher estimate, because that means bigger deficit at same % off.

I'd be curious if the Katch BMR is lower or higher than the Mifflin BMR scooby is using.

Because I'm betting Katch is lower, which means with a higher TDEE estimate, you really had the wrong level of 5 selected.

If you have a way to put more time in to the lifting, then skip the HIIT.

HIIT, even if done properly which I've found usually isn't, mimics the effects of a lifting workout for a sport specific activity for those that don't want to lift. All out anaerobic effort, with rest, repeat. Sound familiar.
If you can do the lifting, skip the HIIT, and use the time there. You'll show better benefit from it.
Most start doing HIIT because they read it burns more fat than steady-state cardio during the repair, despite less calories burned during the workout. Sure, because it's getting closer to what lifting does.

Your hockey is your cardio.
If you can make some of the 3 hrs weekly be lifting, without hurting your hockey play, or rather the intense hockey play ruining your recovery from a food lifting routine, I'd suggest fitting more in.
Then again, there may not be a pretty way around the hockey.

And yes, slowly increase calories, you aren't that bad if total intake was really around 1700. Might go by 100's for 2 weeks, then by 200's after that.

Oh, as you examine your workout and play routine, think about the following fact.
Exercise if done right tears the body down.
Rest for recovery and repair builds it back up, and stronger if diet allows. But recovery will be impaired in a deficit compared to none.

Confirm you have rest in your routine, or else the exercise just becomes one additional stress on the body. Diet already is, lack of sleep, life, ect can all be too. Stress will fight against fat/weight loss.
Lose the stress.

Well, repair probably not right word, but willing to let you move more, which of course burns more, so that's not really metabolism.
One of the body's adaptation to undereating for what it would like is by slowing down your spontaneous activity.
You may have gotten some of that back, plus body willing to repair normal stuff faster.
And, may indeed have become more inefficient metabolically, back to original level, or getting there anyway.

There was a study as to eating in surplus improving daily burns. Of course they still gained fat because being in a surplus. Just like lifters on bulk will gain some level of fat.
It seems your body just isn't willing to make some improvements that require expending more energy daily unless it knows it has plenty of incoming calories to maintain it, and store some extra as fat is signal of that fact.

Some metabolic effects of overeating in man

http://www.ncbi.nlm.nih.gov/pubmed/3538842

If you are indeed eating at real maintenance, you would not lose that gained water weight.
That gained water weight, unless you started eating more sodium too, is glycogen stores finally being topped off with water.
If you were to lose that water weight, it would imply you are not topping them back off.
If not, then not eating at maintenance.

But body is obviously very happy with where it's at and probably losing fat. So for good reset, indeed move on up, really unstress it.

Great job.

Great results. Hopefully that helps any dagging doubts in the mind anywhere.

great news - let us know how you get on!! 12lbs eek am impressed how well you are handling it!!! looking forward to hearing your results!

What metabolic improvements have you noticed? Just curious?

some great positives there - so pleased for you!!

and yes I can see your 12/15 in retrospect is pretty good!!