I came across the following question on p199 of Bob's IREX book:

"Qu 24: The visibility minimum for a particular aerodrome is 4.4km, and the TAF includes the following:
PROB 30 INTER 0204 2000
If your ETA at that aerodrome is 0140 UTC, the minimum amount of holding fuel required if you do not wish to plan for an alternate is:
a) none b) 30 min c) 20 min d) 60 min."

I thought "a) None - my arrival is well before the PROB time of 0400 on the 2nd of the month". Bob's answer was "b) Your ETA is within 30 mins of the forecast commencement of an INTER period."

The BoM's brochure on TAFs says "The period of validity is given in the format ddhh/ddhh". It's not immediately explicit whether this refers just to the validity of the TAF, or the validity of TEMPO and INTER forecasts; but the subsequent examples of TEMPO and INTER forecasts do indeed use ddhh format.

Can '0204' ever mean 'from 0200 to 0400'?

0204 was the old format when most pilots knew what day it was. It now uses the ddhh format . Either you have an old book, or that question somehow got missed in the amendments. I'll check the file and see if I can find it. Thanks for your feed-back.