First try running the Inventory Negative Tier Report and Adjustment in Period End in Inventory.  If that does not fix the issue then use the utilities to correct.  Note that the very first line of the instructions says to make a copy of the live company and test there first.

I don't think any Sage utility fixes zero quantity cost tiers with value.  This is what we do:

Adjust +1 at no cost, post. 

Adjust -1 at the total cost for the tier, post.  Done.

After doing your suggestion this was the outcome..

When doing the adjustments, you have to choose the bad tier for the +1 and for the -1.  That looks like you created your own tier during the adjustments.