28 Tex. Admin. Code § 3.5607
An upward approved deviated single account case rate shall continue for a period equal to the experience period on which it was based, not to exceed three years, subject however to the provisions of § 3.5608 of this title (relating to Annual Review of Approved Deviated Rates). If a change of insurers occurs, an upward approved deviated single account case rate may be continued by the replacement carrier by giving written notification to the commissioner, within 30 days of the effective date of providing coverage to the account, of the new carrier's intent to continue the upward approved deviated single account case rate. The period of continuance shall not go beyond the expiration date originally granted to the previous insurer for that account. If a change of insurers occurs, an approved deviated multiple account case rate shall not be continued by the replacement insurer beyond the date the original carrier lost the account unless all of the accounts forming the multiple account pool are taken over. If all accounts are taken over, the requirements for continuation are the same as mentioned in the preceding paragraph for single account cases.
28 Tex. Admin. Code § 3.5607