How to interpret my Chess Tactics Rating changes?

As you all know, chess tactic training is one of the main methods towards improving in chess. I've been using sites with them for years, primarily ChessTempo. Lately, I've been putting in more work towards improving, and don't know how to judge my current progress:

(TL;DR version is underlined)

My Blitz Rating:

My "Blitz Rating" on the site is the one I feel is the most important and hope to improve, but it has remained pretty steady over the past 6 months, dipping down to the 1710s and rising as high as the 1770s, exactly how it's been since late 2015. Their "Blitz" tactics are like Chess.com's, where time is a factor in rating change, so fast pattern recognition is rewarded. Fast pattern recognition is what I believe to be the ultimate goal in tactic training, which is why I want to improve this specific skill the most right now.

My Standard Rating:

My "Standard Rating" on the site has done very well in these past 6 months! "Standard" tactics have no time-pressure, you either solve them or you don't (I'm not forcing long calculations on them, most are solved within 5 minutes). The problems are a good deal harder than Blitz problems (usually a difference of ~200 points, meaning a ~2000 rated Blitz problem is ~1800 in Standard problems). In 2013, I was in the mid 1600s, then in 2014 I rose up to the low 1700s where I stayed for a long time. I rarely did Standard problems in 2015/2016, but returned 6 months ago, where I had a steady rise from the low 1700s. In early December, I finally reached 1800, and after a great week I'm currently at my highest yet, 1893.3! I may touch 1900, but I anticipate my next month to involve me hovering around 1830 - 1870, which I'm very happy about.

My Tactics Thought Process:

I guess I'd say that during the Standard problems when I find a "great line", I stop, look for a better line, look for possible critical, unexpected moves from my opponent, practically force myself to know this is the best move, the way you'd do in a classical game. In Blitz problems, I try to find a "great line" and just go for it. Sometimes I fall flat on my face, sometimes I speed through nicely. If I can't find any "great line", I'll take the time penalty and search until I find a line I'm at least confident in.

My Statistics:

In the past 2 months, my Standard success rate is 69.7%, my Blitz is 63.6% fast, 8.9% too slow, 27.5% fail. (I average 11 Blitz problems/day, 5 Standard/day)

Question:

What I don't understand is why I'm improving noticeably at the Standard tactics but not the Blitz tactics, nor how to interpret it. What's your take on my steady Blitz skill, but rising Standard skill?

@FishEyedFools, 2nd line: "primarily ChessTempo."