Pos Malaysia released a set of three stamps on December 4, 2006 to commemorate the 25th World Veterans Federation Conference. The stamp set consists three denominations i.e. 30s, 50s and RM1. The 30s stamp has two different perforations - P12 and P13.5. I am not sure which one is less common.
One of the 30 sen duck stamps (Cairina scutulata) released on 26 January, 2006 has two different perforations - P12 and P13.5. The stamp with P12 seems to be less common than that of the P13.5.
A minor error was recorded on perforation of the 30s (Perf. 12) frog stamp sheet (a single sheet contains 20 stamps in the format of 5x4). The upper horizontal perforation of the second row stamps was shifted one-pin-hole down creating first row stamps with larger size and second row stamps with small size (short of one vertical pin hole). The other three rows are not affected by this flaw.
The recent released frog stamps by Pos Malaysia have two perf. varieties - P12 and P13.5. There is no indication of which perf. variety is rarer. However, one needs some effort to gether both the perf. varieties for all the values as different post offices sold different perf. variety on different values.