No. Patisco uses UPS's official authorization method: when you click "Link UPS Account", the page redirects to the UPS website where you enter your credentials and click "Authorize". UPS then issues an authorization token to Patisco. Your UPS password is only entered on UPS's website—Patisco never sees it or stores it.
This is why each company uses its own rates: the authorization is tied to your company's account, so all quotes, shipping labels, and invoices go through your account.
You can revoke the authorization anytime by clicking "Unlink UPS" in the UPS Integration Settings. The authorization itself has an expiration date—simply re-link when it expires. Currently, linking is per-user, so other team members at your company should link their own accounts when they need to use UPS.