Yep. Was standard doctrine for many years now. I wrote about armour vs armour before here and I said the heavy tanks 50/60+ ton was to be engaged in this way: Artillery Saturation, Artillery + cluster sub munitions, aviation.
Although the tanks in the current 'conflict' T-64BV variants are 50 years old, the results are total devastation and would be pretty much the same for current armour engaged in the same manner.
The Grad can use '9M217' rockets. These are specialised Anti-Tank Sub munitions that cut up the armor from the roof.