No, buyer requested cancellations should be mapped using the Buyer Cancellation reason code. If done properly, these cancellations will not be counted towards your overall cancellation rate, which only looks at seller-initiated cancellation rates.
Rithum clients should be sending buyer cancellations as: Accidental Purchase or Buyer Cancelled
DSCO clients should be sending buyer cancellations as: Cancelled at Retailers Request (CXSC)