Well I did not notice that the BM867 had lesser fuses in it. That is just totally wrong. The meter is rated for 1000V CAT.IV and those fuses do not belong there. I will have to include the BM867 in the list of meters that do not meet their CAT rating. Why Brymen would do that I have no idea.
My guess would be cost cutting trumped making sure the CAT ratings were fully complied with, regardless of model.
Same thing with the older BM85x series as well from what I can tell. The BM859CFa is rated for 600V CAT VI, and uses 600V fuses. Some of the rebranded units contain the 600V fuses in their version of the 857, such as the Extech MM560A. At least the BM857A I have, it can be retrofitted with the correct fuses to meet the CAT ratings. Would be nice to confirm this with a more recent unit (keep in mind, the date codes in mine are from 2000), but I suspect it's still the case.
Seems the buyer will have to do their homework if they want to be certain their meter will truly meet their claimed CAT ratings.
That said, it doesn't mean the meters are death traps, just that the user must exercise additional caution when using a meter that doesn't meet it's ratings IMHO (technically speaking, the Brymen I have doesn't meet it's CAT ratings ATM either due to 500V fuses in both locations).
Also seem to recall that some have 600V fuses in the mA location, and 1kV in the A location. Might be worth digging into the 86x series a little deeper.