Whiskas cat foods, 1+ vs 7+

So my lovely cat is now 7, still fluffy and cute as she was a kitten. We have been feeding her 1+ whiskas food. Wondering if there is much benefit moving onto the senior 7+ pouches at this age or are they better for when they're a bit older?

What's usually a good price for a bulk box of the 100 or 120 pack 7+ pouches?