the constitution says we can't be overrepresented, but nothing about being underrepresented.
To add to this, in the history of this nation, the number of representatives has never exceeded one for every 30k people.
If the founding fathers had intended for OP's "interpretation" to be the correct one, they would have adjusted the number of representatives as such in one of the many apportionment acts.
In fact, we see quite the opposite. The ratio has been repeatedly adjusted legislatively to be less than one representative for every 30k people.