Correct. The formats I've described are 35/8, in the same way that IMAX 70mm is 15/70. When talking about 4K scans, that's the scanning resolution perf to perf.
What's important to remember is that when an OCN of a "lazy 8" format film is scanned [VVLA, Technirama], 4K pertains to what would ordinarily be the horizontal on a film element, so while intuitively you might think 8K is more appropriate, the scanner is scanning the equivalent of 2 frames...