(a) After submission to the Board of a hearings officer's report, in an appeal involving employee status or the creditability of compensation, any party to the proceeding may, within twenty days after the mailing to him of a copy of the report, file with the Board and serve upon other parties by mailing to their last addresses of record such exceptions in writing as he desires to make to the hearings officer's findings of fact and conclusions of law. Each exception shall specifically designate the particular finding of fact or conclusion of law to which exception is taken, and shall set forth in detail the grounds of the exception. General exceptions and exceptions not specifically directed to particular findings of fact or conclusions of law will not be considered. Each party shall have ten days after the receipt of exceptions taken by other parties in which to file with the Board replies to the exceptions. The Board may, upon the application of any party and for cause shown, extend the time for filing and serving of exceptions or filing of replies thereto. The hearings officer's report shall be advisory but shall be presumed to be correct. Findings of fact to which no exceptions are taken will, subject only to the power of the Board to reject or modify, stand confirmed.

(b) Further argument will not be permitted except upon a showing by any party that he has arguments to present which for valid reasons he was unable to present at an earlier stage, and in cases in which the Board requests further elaboration of arguments. In such cases, the further argument shall be submitted orally or in writing, as the Board may indicate in each case, and shall be subject to such restrictions as to form, subject matter, length, and time as the Board may indicate.