Not uncommon. The problem is, you are looking at chapter 13 data center, stop. The chapter 13 data center is ONLY a tool for chapter 13 trustees in actually administering the plan payments and paying creditors. It has NO AFFECT on your actually case.
So, best advice, honestly, stop looking at 13 data center. There is nothing on the website that actually concerns how your case will unfold, you chapter 13 plan determines what happens, the nuts and bolts of how the trustee actually administers plan is of concern. Rest assured, you case will unfold as it should regardless of what is on 13 data center.
You can't pay more than 100% of allowed claims and administrative costs. If your tax refunds have made that possible, it does not affect your payment obligation otherwise.
Advice on this forum is for informational purposes only and should never be mistaken as a substitute for legal advice. If you are in need of legal advice, you should consult local legal counsel.
From your description, it is likely that those portions of your tax refund turned over to the bankruptcy Trustee increased your plan base.
A higher plan base would increase the percentage that general, unsecured claimants would receive on their respective claims.