I'll be glad to answer your question as it pertains to me.
I buy chips for about 60 people, trying to get the chips when I am not working my regular job as is the case with most new issue providers and dealers (ie: after work hours). To these people, chips go out after payment is received at the end of the month - even to the 20 or so that have an advance deposit. This is simply because it makes keeping my records straight. End of month - those with an advance get their chips sent, others when check is received.
As for eBay purchases, chips are sent the day after the check is received. Never have I held a check for clearance.
I have developed a fairly decent data base for keeping track of all the transactions but even so, I can't keep track of this, that, and all else. I'm spending 50 to 60 hours a week at work and another 20 or so chasing chips. Sure makes my life less confusing and I've not heard a single complaint from the people I serve. I'll spare you the stories (and names) of "good" CCGTCC members who have ordered well over several hundreds of dollars in chips that at month's end have refused to pay for them (even some who because of name recognition or reputation were sent their chips prior to payment). And, even my order to Playboy wants my money up-front! So, bottom line is simplicity...receive check - send chips. Sure saves hours on bookkeeping.