Within the script you may add the following load-statement:
concatenate(MyProductTable) load 'Total' as Product autogenerate 1;
which extends the product-field.
Further enable all partial sums within the pivot and add two new expressions of:
dimensionality()
secondarydimensionality()
which will return the layer-order of all included dimensions. These order could be queried for your real calculation to branch appropriately.
Like already hinted the replacement of the Year with expressions could be simplify the matter which would require at least 3 expressions with something like:
sum({< Year = {2022}>} Value)
sum({< Year = {2023}>} Value)
sum({< Year = {2023}>} Value) / sum({< Year = {2022}>} Value) - 1
Just play a bit with the examples and you will soon get the wanted information.
