G.R. No. 162322 - Republic vs. Bantigue Point Development Corporation

Application, Parties and Property
On July 17, 1997, Bantigue Point Development Corporation filed with the RTC of Rosario, Batangas an application for original registration of Lot 8060, Cad. 453-D, San Juan Cadastre, Barangay Barualte, San Juan, Batangas (area ~10,732 sqm; assessed value ₱4,330 + ₱1,920 + ₱8,670 = ₱14,920).
The Republic of the Philippines filed its Opposition on January 8, 1998.

Trial Court Proceedings and Appeals
The RTC issued orders on July 18 and August 7, 1997 setting the initial hearing (first at 96 days, then at 110 days), and on March 31, 1998 motu proprio transmitted the records to the MTC of San Juan for having assessed value
The MTC declared general default, received evidence (tax declarations, deed of sale, CENRO certification) and on January 22, 2001 granted registration.
The CA, on February 13, 2004, affirmed the MTC: it applied estoppel by laches and found sufficient proof of open, continuous, exclusive, notorious possession.
On April 12, 2004, the Republic filed a Rule 45 Petition before the Supreme Court raising only questions of law.

Can the Republic, having actively participated below, still question the MTC’s jurisdiction for the first time on appeal?
Did the MTC properly acquire jurisdiction over the application for original registration, specifically:

Were the 90-day and five-day periods for setting the initial hearing under the Property Registration Decree jurisdictional or directory?
Is the MTC’s delegated jurisdiction under Sec. 34, Judiciary Reorganization Act limited by land value based on selling price or assessed value?