Recoding was not carried out.
Code 2 (professional or technical) represents a mix of all levels.
Mostly it may contain medium, but it is likely to contain some low and high as well.
Since 25 percent of the population is concerned, LIS decided not to recode.

If LIS users want to pursue a recode they may do so on their own responsability.
The mapping below may serve as suggestion. 
The problematic category is pointed out.

PEDUC							     ISCED97	   LIS recode
  0  missing/in school								9
  1  primary and complementary							1
  2  professional or technical							2 or 1 or 3 ?
  3  secondary (high school)							2
  4  superior (university)							3