Didn't 'the Society' make blood transfusions a conscience matter a few years back, like when they came out with "it's ok to take 'blood fractions' " doctrine?
If so, that would explain why there is a discrepancy among JWs. Many of the older JWs, such as my Father, ignored this and held steadfast to the 'blood is forbidden' ideal. Younger JWs don't seem to be all that enthusiastic anymore, particularly if it means they'll die.