A webpage cannot tell you that your job is exempt. The building department that covers the property can.
Start with the jurisdiction
San Diego County is not one building department. A house in the City of San Diego is not reviewed by the same counter as a house in Chula Vista, Carlsbad, or the unincorporated county. Ask the contractor which department they believe covers the address, then confirm it yourself if the answer is casual.
What the City of San Diego has published
Information Bulletin 203 describes conditional exemptions and a no-plan permit path. Read the bulletin, then ask Development Services whether the work you are actually doing qualifies. Same-size glass in a sound frame is a different conversation from enlarging an opening or cutting a new header.
Put the paperwork on the quote
The useful line is who calls the department, who pulls any required permit, and who meets the inspector. If that line is missing, you do not yet know the scope.
Pane Pro SD does not pull permits and does not install windows. The contractor you hire does, if the department says a permit is required.
Related: a bedroom needs a way out.