Its true overall NAV will decline with the tender offer but NAV per share will increase as a larger proportion of shares outstanding will be retired than the proportion of assets than will be consumed.
I personally think the 95$ ratio is fair as those who don't tender will benefit by the NAV/sh increase but will be hurt by the small increase in proportionate expenses. Thus this should be a rough balance. There's no need to tender if one doesn't want to bother but if one is willing to tender the higher price will benefit those shareholders to the extent that the shares get accepted.
The ratio of acceptance should be higher than normal since there is no obvious injury to those that don't tender. I am willing to guess that more than 60% of shares tendered will get accepted. Most of the time acceptance of 15% at 98% NAV would probably be less than 30% and non tendering shareholders would wind up getting hurt to boot.