Whilst fully accepting that BME is known shite, do you know when your battery was manufactured? I suspect that Nokia don't need to produce these very often, and may be selling stock that's easily a year old. If so, then a capacity loss of anywhere from 4-20% is entirely to be expected (see http://en.wikibooks.org/wiki/Battery...ure_and_charge) and your BME may not be as wrong as you think.

Popular wisdom is that the Scud batteries from Lucia Lui are about the best available, they're quoted as 1445mAh and this is realistic, they've been measured at 1400-1500mAh by multiple users. Mine measured in at ~1430mAh when I got it (according to bq27200) and reports at ~1350mAh now, on the same device, after nine months of use.

Hopefully your BL-5J comes good after a few charge cycles, but if not - try a Scud.