This has nothing to do with the wallet you're using. Any wallet you use with your current address will show the exact same sizes of transaction, since this is based on the data used in the transaction, that is, the inputs and outputs of your transaction. There's a formula you can search for (I don't have it off my head), but in general, the more inputs and outputs you have, the larger the size of transaction (with inputs being the main contributor).

The median size of 226 bytes is what you have if you use only 1 input with 1 output (non-Segwit).