More bike intervals, more interesting numbers. And questions.

BIKE 19 miles in 67 mins, 4x7 min (3 min) intervals at 75%.
SWIM 2500y in 55 mins, 8x200 (20s) alternating swim and pull
BIKE COMMUTE 6 miles

The plan called for 4 7-minute intervals at 75% effort, with a 3-min 60% rest. To stay focused on effort, I didn't watch my speed during the intervals. I adjusted the rear gears to keep it feeling like 75%, this was only 1 or 2 gears difference. All intervals worked out to about 18.8 mph.

#1: 2.2 miles, ave heart rate 105, mid ring, no rpm data here
#2: 2.2 miles, ave heart rate 107, big ring, ave 82 rpm

I was surprised to see the intervals so similar, for some reason I thought I'd be at least a little faster in the big ring or at least working harder. I repeated #1 and counted rpms again:

#3: 2.2 miles, ave heart rate 105, mid ring, 82 rpm

Huh?! One last time, now instead of thinking about effort I focused on higher cadence. This took more "mental energy" since it wasn't a habit. I expected my HR to be higher, but:

#4: 2.2 miles, ave heart rate 107 bpm, mid ring, 88 rpm

!?!? So now I have 3 tests, and 3 ways to ride the trainer for the same outcome. Which one is right? Am I doing anything wrong? Am I just riding "bored" and not really working like I should be?

I wrote this up as a Question For The Experts for the Club newsletter. Selfish, but maybe a win-win in that I get an answer, the newsletter gets an article, and some other reader learns something. A win-win-win!
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The bike commute was COLD. I know what it means maybe to freeze your tail-feathers off -- the energy expenditure to get warmed up again is sure to be a burner! I thought it was warmer outside, but as I'm leaving I learn it's in the mid-20's. I found out later the wind chill was 18F! My thumbs were painful, my hands had blue/gray areas, and my feets suffered. And I still have to ride home today...
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The swim was a make-up for Monday's missed swim. The plan didn't have a schedule swim today, so that means I'm planning swims for Thursday and Friday as per schedule and on Sunday as per Club Postal Swim. So to avoid fatigue I switched the 70% 8x200 swim to an alternating swim-pull. The swim I worked on getting higher in the water. The pull I worked on my arm position in front of my head. I was looking for the strong catch, that smooth glide in the water, and a relaxed effort.

I timed the intervals, the swims were generally 4:00-4:10, the pulls about 10-15s faster. Pulling is definitely much easier, does that mean I'm losing that much of my swim to back-end drag?! What is the contribution of the focus on the front end do for the pull time, cuz I focus less on that during the swim intervals.

Questions, questions...need to do some research!