The county commissioners cannot dictate to this ELECTED BODY what to say - separation of powers and all that. Here is the relevant portion of a Chester County Court decision with the entire context to follow - it's the SAME situation only 35 years ago!
The Study Commission has endeavored to provide every voter in Chester County with at least a brief summary of its Report and Recommendations. We find such endeavor not only lawful, and within the power and authority of the Study Commission as bestowed upon it by the cited sections of Act No. 62, but indeed a salutary and worthy effort,
entirely consistent with the noble traditions of this great and historic county.
Court of Common Pleas of Pennsylvania, Chester County. McDermott
(Editor's note: The above suggests that the County Commissioners may not censure what the Home Rule Commission has to say, but the portion quoted does not say that the County Commissioners have to provide the funds to pay for the advertisements.)