Hertl and Jumbo Joe are underpaid. I have to think Hertl will be around 5.5-6 mil give or take and Jumbo is still gonna want his 6-7 per year.

Jumbo is 40 years old coming off two knee injuries. He was already on record as saying he wants to stay at the Sharks and is happy to take a pay cut to keep that.
Furthermore, we know from last season he had agreed to a lesser amount to keep Marleau, and the $8M was more as recognition of his service rather than his value. From 2008-2009 season to 2016-17 his cap hit went from $7.2M to $6.75M, so there was already a downward trend. Taking into consideration, I would be surprised if he signed for more than $5M.

As for Hertl, his production this season was the same as the last in his ELC (46 points). He was given a 2 year $3M contract. I think he has shown his potential, and capability to play away from Jumbo, but not enough to significantly increase his AAV. It is also important to remember he is an RFA, so there is a bit more leverage for the Sharks. A 4-5 year deal means he would be 28-29 at the end of the contract which gives him a good opportunity for a bigger pay day when he is in his prime.

Just my opinion, though and I could be way off - just wanted to share my thought process.