You should only use the calculator if you use the default value – with or without land use change emissions:

Take the result display on the tab “BONSUCRO EU RED Output” cell C15
Add 4.6
Note the total – this is the default value plus any land use change emissions
calculate: [94 (new fossil fuel emission value) – total]/94 this is the total saving in %
For example if there is NO land use change:
“BONSUCRO EU RED Output” cell C15 = 24
24+4.6 = 28.6
(94-28.6)/94 = 0.695 – 69.5% saving