Your son does sound likes he's doing well, it oculd be over zealous playleaders, but it oculd also be taht the playleader has seen it so many times before that she knows the signs..
How does your ds play? does he pretend and I don' mean act out scenes from films/tv [asd and as children can act out from memory]does he get preoccupied with ordr and specific aspects of toys [wheels for example] does he have a particular line of interest [trains, space,etc] is his speech animated or monotonous when talkign about subjects he is intestested in...
And does he fully nderstand what he's hearign and saying? tahst a difficult one to guage, and that's why a SALTs been involved. Have you been referred ot childrns audiology? the problems with pronunciation, frustration and behavioural probelsm can also be associaed with hearign loss/impairment from glu ear etc.
Whatever happens, if your son is pu forwrd for a fulla ssessment etc it mgiht help to prepare for teh worst and hope for teh best, that way if you did get a dx, the world would fall out from under your feet.
I am sorry if I came across badly in my first post, I thik that becuase my son is Autistic I get a bit defensive when peoel think its this big bad condition, its hard yes, but its not teh end of teh world, my boys is bright, social and has a killer smile, what he lacks in speach, social interaction with stranger and imaginative paly, he more teh makes up for with inventivenmess, problem solving, and persistance.
must go, a dor do dah is required [thats a cup of juice btw]