Question about GE strength & special sites

[solmyr]

If a global enchantment is casted in a province with special gem discount magical sites, say e.g. blood 40 site, then how is the strength of the GE in terms of counter dispelling?

e.g. A blood GE require 100 slaves is casted in a blood 40 province and only 60 slaves are used due to the bonus of magical site. When someone else tries to dispel the GE, how will the dispel mechanism apply in this situation?