"A 1.8C difference" expands as "A difference of 1.8C" expands as, and here's the ambiguity, either:
"An absolute difference of 1.8C, or 274.8K, measured between A and B"
or
"A relative difference of 1.8C, or 1.8K, is added/subtracted to A/B in order to reach B/A"
I don't think the context-free variant with K will improve understanding and decrease confusability in this discussion context, but I appreciate the pointer about it in general. I'll take a lot more care around it in a future thread about space apparel!
No it doesn't. The absolute difference[1] of 1.8°C is the same as 1.8K; they have the same scale. The subtraction of values cancels out the offset.
A relative difference[2], usually given in percent change, has problems with a unit that has an offset zero like Celcius, but that isn't what anybody is using here. It's more than simple subtraction; you have to divide by the reference value.
"An absolute difference of 1.8C, or 274.8K, measured between A and B"
or
"A relative difference of 1.8C, or 1.8K, is added/subtracted to A/B in order to reach B/A"
I don't think the context-free variant with K will improve understanding and decrease confusability in this discussion context, but I appreciate the pointer about it in general. I'll take a lot more care around it in a future thread about space apparel!