Can you find a place to do hydrostatic (water tank) body fat test? You can find DEXA at some universities or some gyms now have BodPod (measures by air instead of water).
It seems like bodyfat calipers are pretty cheap. $5-15 via a google search. Hrvk, I should order myself a pair to along with a balance scale and mirror check.
You can use this. I tested far lower on a 3 site caliper test because my thigh and tricep were under 10% but my abdomen was 20% (which is about what I tested on the tape test). Tape test was 20 but 3 site was 13ish and I think a 7 site would have been less since most of my bodyfat would be on my abdomen and suprailliac (lovehandle).
Note, I tested my bodyfat when I weighed about 84-85kg. I bumped up to just under 82 yesterday but should go back to 81 once I normalize from a carb binge. I'm sure I would have tested at even less when I made weight at 77 a few weeks ago.