Price management structure doesn't match.
For strikethrough to work the rate or policy that you are striking off of must have a price structure that matches the rate you are using.
This must be either per room or per adult for both rates.
Linear or non-linear price structure.
If you have linear or non-linear pricing set up on the rate, then for strikethrough to work the rate you are striking off of must be in the same format.
Price on the rate that you are striking off of is lower than the price of the rate you are using.
If the price on the rate that you are striking off of is lower than the rate that you are using then strikethrough will not work.
Your strikethrough policy is not marked as active.
You may have set up the strikethrough policy but not marked it as active. If it's not, mark as active and save changes.
The policy period set up for your strikethrough policy has ended.
If you set the strikethrough policy up to run over a certain period and that period has ended the strikethrough on that policy will no longer work.
If non of the above are the reason for the strikethrough not showing contact support.