Does a disk with only an extended partition needs alignment ?

We all (storage freaks) know that for better performances, partitions need to be aligned to disk sector boundaries in order to avoid performance impact due to r/m/w issues generated by data written across multiple sectors.

I was told a long time ago that if you create an extended partition on a disk, with no primary partition, you do not have an alignement issue, because you do not have an MBR. Is that correct ?

This seems wrong to me because whatever the partition type is, if your disk is MBR formatted, you will have an MBR anway on the disk which makes it by default misaligned with filesystem partitions…

If anyone can explain and argument an answer, I would be grateful.