SAC Thresholds, Compare to measure missing

[sevans]

Hi

Within a story I am trying to apply a threshold on a measure to apply conditional formatting depending on its value compared to another.

When creating  a threshold from the ribbon menu I can only create account based thresholds, I believe due to the model containing an account dimension. To get round this I select the measure header in a table and from the context menu (from right clicking) select thresholds here this allows a measure threshold but this does not allows a threshold where the measure is compared to another measure as shown below.

I should see this