There is official interval rules from the CDC that the CIR and dr. are following stated that there is minimum interval for DTaP and Polio between first dose and the second dose, please update.
See the link
https://JLSSolutions.com/QA/?qa=blob&qa_blobid=9753666035852202851
https://www.cdc.gov/vaccines/schedules/hcp/imz/catchup.html