Similar story: asked for an increase and got told
> […] our mission is to improve Internet security by increasing the adoption of DNSSEC. [We therefore expect users to enable DNSSEC for their domains.
> Would you be willing to do that?
Wanting to increase the adoption of DNSSEC is fair, but couldn’t this be all self-serve? It’s almost as if they don’t want people to use them.
They've actually just done that, your limit automatically gets increased if all your domains are secured.