Hello ‘CTWEBER01’ and welcome to the forum.
The paint code site I’ve used before is in the fairly long post I wrote, which is at the top of my show us yours page.
It shows that 21T does comprise two further codes of 4K6 (Reddish Brown Met) and 4K1 (Light Beige Met or Light Beige Met-1).
Anyway looking at the picture you linked it’s not at all obvious which is which and I can understand the problem.
My van is colour 9D4, on the plate, which is also two-tone and these are shown as 6L3 (Greenish Silver Met) and 8H4 (Dark Greenish Blue M).
I can tell you that my van is distinctly silver-ish at the bottom (first code) and very green-ish at the top (second code). If this continues across all two-tones then yours might be 4K6 (first code) at the bottom and 4K1 (second code) at the top.
If this is more than just curiosity and you’re looking to get some paint I’d suggest taking you van to a paint workshop. They will use a special sensor to determine the exact colour it is and how to make up the paint based on various components. If you were to apply either 4K6 or 4K1 based on the factory recipe that the workshop will have access to then these likely won’t look right on the vehicle due to fading and the lacquer and whatever flattening process was carried out to both the colour and lacquer coats.
Hope that helps and it would be useful if anyone else with a two-tone Hiace (other than 9D4) can reassure that the first colour is the lower and the second is the upper.