This will certainly not be of any great danger to senior cats, however we do prefer that the formula to include is slightly lower protein, phosphorus and calories is fed to help reduce the ageing of the kidneys and preventing obesity as cats become more sedentary in the later lives.
Your Premium food does have a senior diet which I would consider switching to.
Alternatively ask your Veterinarian which diet is best suited to your cats ageing medical needs as there may be specific conditions that your cats have that I may not be aware of.
Martin Slome DVM
Centre Street Animal Hospital
7700 Bathurst Street Units, 40-42
Tel. (905) 771-9855