back then we use aggregate system rather than how many As, Bs or Cs. aggregates are calculated from 6 highest scoring subject that u scored and add them all together. meaning, if a person scored A1, A1, C3, C5, C5 and C5, his aggregate would be 20. the highest aggregate would be 6 (from six A1s).
the problem with this method is that, the number of students scoring 6 aggregates was increasing every year. there is no other indicator above 6aggregates except how many A1s they scored. so in 1980s, it's enough to say "i got 6aggregates!". in the 90s u gotta say "i got 6aggregates with 8 A1s".
the other problem with the aggregate system was people tend to score 6 subjects and dump the rest. which was what i did LOL. i concentrated only 7 out of 10 subjects. the other three got C5, P7 and P8
hehehe. alot of people exploited this system back in those days. they signed up as pure science student, yet scored only the non-science subjects, but still scored 6 aggregates. u can still get into science based courses with these results.
the new system we have nowadays put more equal weightage on all subjects. so this would produce more rounded students. also, SPM format nowadays are more open, where u can select from about 20++ subjects, apart from the compulsory ones.