It does look like PA charges an extra fee.

From PennDOT Driver and Vehicle Services

How much does the REAL ID cost?

You will pay a one-time fee of $30, plus a renewal fee (current renewal fee is $30.50 for a four-year non-commercial driver’s license or a photo ID). The expiration date of the initial REAL ID product will include any time remaining on your current license or ID card, plus an additional four years, unless you are over 65 and have a two-year license.

This expiration date structure means that you won’t “lose” time that you've already paid for. After the initial REAL ID product expires, the customer will pay no additional fee, beyond regular renewal fees, to renew a REAL ID product.