Non-inclusion of the Municipal Administrator in the BAC will be illegal?

The LGU reorganized the Bids and Awards Committee (BAC) and pass Executive Order to the Provincial Office. Now they returned the EO for the reason that Non-inclusion of the Municipal Administrator in the BAC will render the said EO invalid, and all procurement transaction conducted by the reorganized BAC is illegal.

It is mandatory to have a representative from the office of administrator, budget office, Legal office, Engineering Office and General Services Office? How about in the absence of one or two of the above mentioned offices, can be the composition of the BAC will be illegal? Do the said representative need also a career eligibility?

No because the phrase "but not limited to" is not inclusive.

illegal if the the Municipal Administrator position as BAC Chairman was replaced by a non career , non permanent employee !