No dear all ECAs do not require original documents. I am surprised to know that they all are working in Canada for the same purpose but requirements are totally different for every ECA company and moreover evaluations for same documents also differ between them. If WES evaluate a candidate as Graduate same candidate evaluated by other company as Masters.
CES do not require any original document or even any document directly from any institution. They also do not require SS and HSC attested copies, just simple copies will serve the requirement.
"Please refer to additional notes below regarding documents acceptable by CES:
HEC (Higher Education Commission) attested photocopies of the Degree Certificate and Mark Sheet/Result Card sent directly to CES by the HEC. (HEC can only attest documents for university-level degrees, e.g. Bachelor, Master, Ph.D.)
OR
Applicants may request that HEC place the attested copies in an official signed and sealed envelope. These copies can be in black & white or colour. The applicant can then forward this sealed envelope to CES with their application, along with their own copies, a signed application form, and payment.CES must be able to confirm the attestation on the HEC website."
http://learn.utoronto.ca/internatio...e-education-service-ces/country-list/pakistan