You said
"I recently sold that $5 Last Frontier Can Can chip for $50, in similar SU condition."

But then you stated you sold a set of 4.
There are far less $25s and $100s around. They always sell for 2 to 3 times the price of the $5. Same with the $1.
The $5 only represents about 10% of the value of the set so you cant really compare.