Weight-wise that means legacy transaction's signatures have 36 more weight than Schnorr transaction's signatures.
Basically the calculator is using a tiny and limited subcategory of P2(W)SH scripts (standard multi-sig redeem scripts with compressed public key with nothing else inside).
It also has the wrong presentation that looks like you could have more than one public key and/or signature for P2(W)PKH inputs although the calculation is correct regardless of the textboxes.
Secondly, my comparison was between single signature/public key needed per input and it could be extrapolated to more while considering the pubkey aggregation Schnorr offers.
Schnorr signatures are reducing the size, if you have one signature in your input (whether it is P2PKH or P2WPKH or P2SH or P2WSH) the reduction is as I said in raw bytes which you can easily convert to weight and virtual size.
If you have more signatures in the input (whether P2SH or P2WSH) the reduction is as I said + the aggregation reduction which is when you only have 1 signature + 1 public key instead of n signatures and m public keys.