Example: Transiting Venus square natal Saturn is not the same as transiting Saturn square natal Venus.
Transiting Venus square Saturn = (just one example) For a week or so, your social life is causing issues with men, elders, authorities, or your responsibilities.
versus
Transiting Saturn square Venus = (just one example) For most of this year, authorities, elders, responsibilities, or men will cause issues with your social life.
To me, there is a difference in both the sources of conflict (transiting planet = external circumstances) and what must be adjusted to compensate (natal planet = native's perspective/attitude/etc.). Many astrologers treat them as basically the same but I tend to interpret things in a more traditional, non-psychological way.