Could someone please explain the difference between “Obverse 1.a (Mintmark near “JOSE RIZAL.” Regular hair.)”, ”Obverse 1.b - Frost (Mintmark near "JOSE RIZAL". Fine hair details. Frost.)", "Obverse 1.b (Mintmark near "JOSE RIZAL". Fine hair details.)" and "Obverse 2 (Mintmark above L of "RIZAL". The R in “REPUBLIKA" above the first I in “PILIPINAS”.)”? The page has pictures, but there is no mention of obverse 1.a/1.b, and the MMs are base/no base, not placement compared to Rizal.