JR Pass / Gran Class questions

Hi Japan Guide folks,

Got a couple of questions re: JR pass

1) we purchased Green Class JR Pass and want to try out the Gran Class experience once. Wondering how the upgrade to Gran Class works?

Sendai to Shin Hakodate
Standard 17,950 yen, Green 24,410, Gran 32,790

Is the top-up amount the difference between 32.790 and 24.410 = 8,380 ?

2) Will the complimentary bento & drinks also offered in the Sendai-Hakodate route and not just the main Tokyo-Hakodate route? If yes, this will make the upgrade more justifiable

3) We purchased JR passes in the past before but always book the tickets after we arrived in Japan. Just checking if advance ticket booking is possible even before JR pass is activated? Our itinerary includes Yufuin no Mori at the start of our trip and we heard this train is very popular and often sells out

Thank you in advance

You would be paying the full GranClass seat fee, not the difference.

My understanding is that you have to pay for the total Gran Class seat fee, makes no difference whether you have normal or Green Class JR pass

The fares from Sendai to Shin-Hakodate-Hakuto are:-
Reserved seat JPY8,910 (base fare) + JPY9,040 (seat fee) = JPY17,950
Green Car JPY8,910 (base fare) + JPY15,500 (seat fee) = JPY24,410
Gran Class JPY8,910 (base fare) + JPY23,880 (seat fee) = JPY32,790

So you have to pay JPY23,880 for upgrade to Gran Class

https://japanrailpass.net/en/about_jrp/route/
https://japanrailpass.net/about_jrp/route/
また、東北新幹線・北海道新幹線 ・上越新幹線および北陸新幹線のグランクラスを利用する場合は、別途特急料金、グランクラス料金を支払わなければなりません。
Also, when using a Gran Class car on the Tokaido, Hokkaido, Joetsu or Hokuriku Shinkansen Lines, the limited express fee and Gran Class fee must be additionally paid.
(there seems to be a mistake in English version. "Tokaido" in English version must be "Tohoku".)

total price = basic fare + limited express fee + granclass fee

whatever you buy JR pass of green class or normal class, you have to pay limited express fee again.