House does not Cool Down

Afternoon All,

With the temps increasing I have noticed my house only cools down ~10 - 15 degrees from the outside. I have a Lennox 2.5 ton unit (HSXA12-030-230-01) with a TXV. I have cleaned the EVAP and Condenser coil and installed a new filter. I grab the following temps and pressures after running the system for 15 mins:

Refrigerant: R410A

Outside Temp: 28.1 C

High Side:

268.5 PSI = 31.3 C

29.0 C Line

Low Side:

92.5 PSI = -2.4 C

19.0 C Line

This to me seems like low refrigerant. Is this a correct assumption? Thanks for the help!