Yes, very confusing.
SPXW (Weekly) Afternoon Settlement Hybrid System (Electronic and Pit traded) many people send quotes electronically
SPXQ (Quarterly) Afternoon Settlement, Pit Traded, One "group" sends quotes into system
SPX regular. Morning settle, Pit traded, one "group" sends quotes into system.
SPXPM Afternoon Settle (no weekly's as SPXW are essentially the same thing) Electronic and Pit traded, Multiple "groups" send in quotes.
In the SPXPM, SPXW if you see a quote, you can trade instantly electronically. In the SPXQ, SPX, it may take awhile to be filled as a broker may be holding the bid or offer and another broker will have to find him.
At least with the ES I've never had a problem getting a fill...even those way OTM..perhaps because ES is all electronic.dunno
In general, you don't want to be asking for a market in a voice broker unless you have a proper vol surface and can at least guess where the mid should be.