Are any of the Asian made Flukes AC-coupled?

[rsjsouza]

I have no idea what that stage three DC bias is but keep in mind that the meter is only 50,000 counts.  Even your stage 2, what you have now would work better if you really need to get down this low.

I had the impression the OP mentioned a minimum of 15mV_AC on top of the DC bias. If so, the 5V_AC range with 50000 counts has enough resolution to see this signal. 

[Valver]

Isn't the minimum resolution limited due to the True RMS converters ?

From Fluke 179 spec sheet with regard to the 600mV range:

"Unspecified input levels on the lowest ranges are:•AC voltage: below 5% of 600 mV AC, or 30 mV AC"

From Fluke 80's series V manual:

"AC conversions for Model 87 are ac coupled, true rms responding, and valid from 3 % to 100 % of range, except 400 mA range (5 %
to 100 % of range) and 10 A range (15 % to 100 % or range)"

i would imagine that the Brymen has similar restrictions. 3% of 5V is 150mV (+40 digits and .8% accuracy if I read the specs correctly).

rsjsouza, I did notice that your readings were quite similar between meters. Perhaps because you were using a sine wave?