The pleiades are shown as a symmetrical cluster in other ancient art of other cultures, aren't they? Achilles Shield maybe?
There is only a wee blue mark for them ,btw the bloke who's site that is from has some very odd dishes that require more salt than all the UK motorways combined .
If they haven't changed , the problem could be interpretation of seven points that don't represent the cluster or , are the artists are just being lazy which seems a bit odd ,would they do the same for Orion or the Plough .?