Hi acctngnoob,
I am a CPA with in Big 4 Tax, and the short answer to your question is that it depends on the designation on the type of CPA License that you want. (General Experience or Attestation experience.
The General Experience designation requires 1 or 2 years of work experience under the supervision of a CPA in either a public accounting or non public accounting firm.
The Attestation Experience designation requires 1 or 2 years of work experience under the supervision of a CPA in either a public accounting or non public accounting firm, with at least 500 of the hours as attest hours for those who want to sign attest reports.
The forms differentiate which designation you are applying for as a CPA and in which environment you obtained your work experience. For the attestation designation, you have to have someone certify that you worked a minimum of 500 attest hours. While the general experience designation, you just need to have someone certify that you worked under the supervision of a CPA under whichever pathway you choose to apply.
In my firm, most people in tax opt for the General route, and are able to obtain their license pretty quickly. However, if you are interested in qualifying for the Attestation route, you can always attempt to do an audit rotation to meet the 500 hour requirement, which I have seen a few people do.
Hope that helped, and good luck!