I have not seen them included in a delay damages calculation but in theory you could. One problem would be making a calculation in the absence of any tendered information although there is plenty of reasonable cost information available to make an assessment. A further issue would be assessing the share affect under a main Option C, as you would have to make an assumption whether it is likely to be pain or gain.
Delay damages also tend to be influenced by commercial decisions. If the amount is high then the Contractor would need to consider this risk, especially where the programme is 'challenging', so it could be counter productive to the Employer.