Just to reply to myself... so anyone else with a Celsius temperature Fujitsu A/C unit has the answer that I've spent hours testing to figure out.
Firstly, I have tested David's (@dabrams) PDF file against my Fujitsu AR-RY3 remote control, and after initially banging my head against MSB vs LSB etc (first time I've ever decoded pronto codes into bitmapped values), I had a nice spreadsheet with my individual Pronto burst pairs on rows, grouped into bytes, with any bits mapped appropriately etc. Then I just did a bunch of testing to see what Celsius values on the remote control, map to which hex values within Word 9 (Chart A on the PDF). Here are my findings, David I don't know if you feel like updating your PDF or not, but here's the info, "dC" is degrees C shown on my remote, "Bits" is the bits seen in Word 9 bits 4-7, Hex is the hex value, DocSez is what @dabrams' doc listed for that hex value. FYI, other A/C systems in degrees C tend to use the whole available range for that 4-bit value, i.e. 0x0 = 16C, 0x1 = 17C and 0xF = 31C. I can't test if this is the case with Fujitsu since my remote doesn't let me pick those values. The rightmost column FequivC is simply docF converted to Celsius using the real-world conversion rate (C = (F-32)*5/9), I just wanted to show that dC is not just a direct F-to-C conversion, Fujitsu have for the most part simply truncated the decimal part of the equivalent Celsius value, but above 28 degrees that no longer holds true.
Lastly, one more addition to the PDF should be made: your Fujitsu system doesn't have a Master Mode called HEAT. Mine has Auto, Cool, Dry, Fan and Heat. The PDF lists this for byte 10:
00H = Auto 01H = Cool 02H = Dry 03H = Fan
Mode "Heat" uses 04H.
Hope that's useful info, if anything just to confirm that David's document holds true for my AR-RY3 remote, which I am massively stoked about. It took me a couple of hours to fix up my wrong assumptions (about bit-ordering) and fix my spreadsheet, then magically my values matched his.