You don't seem to understand how a charitable remainder trust works. The assets are placed in trust and then a fixed percentage of 5-50% of the trust value is distributed to the Kriens himself as beneficiary. Upon Krien's death, the remainder of the assets will be distributed to the charitable beneficiary.
So Kriens ends up with a lifetime annuity and an immediate charitable deduction which was doubtless used to shield some other part of his stock sale from immediate taxation. Since Kriens would want to see the maximum possible annuity, he has every interest in optimizing when he sells his shares.
I see no way that Kriens relieving himself of 75% of his remaining stake in the company cannot be seen as some kind of sign that he considers that price to be a favorable valuation of the shares going forward.