Congrats on the find nickelsearcher and yes that would be a step up ladder. I would imagine you noticed the first note posted to start this thread was very similar. Most people think of ladders as 12345678 and this topic was meant to open their eyes a bit and get them to see they can be more than that. Naturally the more valuable ones are single digit full ladder notes, but to me (and others) these types of ladders have value too. As far as terminology is concerned here are a few names to throw around:
12345678 - Perfect ladder (step up)
98765432 - Ladder (step down)
18171615 - Double digit ladder (up)
20191817 - Double digit ladder (down)
88776655 - Quad double ladder (down)
00112233 - Quad double ladder (up)
11112222 - Quad ladder (up)
44443333 - Quad ladder (down)
96599660 - 4 digit ladder (step up)
58895888 - 4 digit ladder (step down)
12344321 - Radar ladder
23452345 - Repeating ladder
20304050 - Ladder (counting by ten)
00000123 - Low serial ladder
62743815 - Scrambled ladder, Broken ladder, mixed ladder, or a sudoku note
But of course some people will naturally call them with slightly different names, but that is OK I guess

You will also see a lot of garbage on
ebay referred to as a ladder, I don't consider half (or more) of the junk serials I see on the Bay as "ladders". I will call a serial (like the one I posted above) 00543321 as a "ladder-ish" serial number. But try as I might I can't see something like 71234259 being considered a ladder just because it has 1234 in the serial.