Kyushu Rail Pass Northern Kyushu - Validity

I have read the Kyushu Rail Pass details on this site:

http://shop.acprail.com/#/pass/kyushu_rail_pass/

and I'm a little bit confused whether I can travel between Hakata and Kumamoto by Shinkansen trains or not. First is written:

The Northern Kyushu Area Rail Pass is not valid on Shinkansen Tsubame trains

while in different place is written:

The All Kyushu Area Rail Pass can also be used for Kyushu Shinkansen "bullet" trains.

Explanation at japan-guide.com doesn't mention any restrictions about using bullet trains with Kyushu Rail Pass Northern Kyushu, however quoted conditions suggest that it is either not allowed to travel by Shinkansen at all or only Tsubame is not covered (Mizuho and Sakura still possible). Does anybody know how does it really works?

Thank you in advance for your answers.

and I'm a little bit confused whether I can travel between Hakata and Kumamoto by Shinkansen trains or not. First is written:

The Northern Kyushu Area Rail Pass is not valid on Shinkansen Tsubame trains

The particular page is not up-to-date. One year ago, the Kyushu Shinkansen was completed between Hakata and Shin-Yatsushiro. Since then, Tsubame trains (and the other trains along the Kyushu Shinkansen) run all the way from Hakata to Kagoshima. And since then, the Northern Kyushu Pass is valid on all shinkansen trains between Hakata and Kumamoto!