Is there power-sharing between SC, Congress?

The Supreme Court has the constitutional power to promulgate rules concerning pleading, practice and procedure in all courts (Art. VIII, Sec. 5[5], Constitution). The power of Congress under the 1935 and 1973 Constitutions to repeal, alter or supplement rules concerning pleading, practice and procedure was taken away in the 1987 Constitution (Echegaray vs. Secretary of Justice, G.R. No. 132601, January 19, 1999).

In short, in the past, there was power-sharing between the Supreme Court and Congress. However, the present Constitution has (according to the Court) already eliminated this setup, allowing the Court to acquire a monopoly of powers regarding pleading, practice and procedure.

However, others cite Article XVIII (Transitory Provisions).

"Section 10. All courts existing at the time of the ratification of this Constitution shall continue to exercise their jurisdiction, until otherwise provided by law. The provisions of the existing Rules of Court, judiciary acts, and procedural laws not inconsistent with this Constitution shall remain operative unless amended or repealed by the Supreme Court or the Congress."
It would seem, at first glance, that the Constitution intends the Congress to have the power amend or repeal the Rules of Court and judicial acts. However, an interpretation more consistent with a more independent Supreme Court is reddendo singula singulis.

"Rules of Court" and "judiciary acts" may be amended or repealed by the Supreme Court. "Procedural laws" may be amended or repealed by Congress.