Begin an intelligent person, you know that there are big variances between different ELISA and different Western Blot tests. So what holds true with one, might not with others.
That said, there will be published a study in 2010 where you can see that both the specificity and the sensitivity is higher with the Mikrogen Western Blot, than for all the ELISAs.
ELISA tests often show a "serological scar" (often referred to as false positive) in areas with much lyme. Rates of around 1/3 of healthy blood donors testing positive with the ELISA is not uncommon.
Anyway, point is that the Western Blot does not have to produce more false positives.
And another point, which is off topic, is that I think that the 1/3 testing positive do in fact have a latent infection, but feel completely well (and will most likely do the rest of their lives).
Where are you getting your information from??? I have never heard this before.