There is a thread in FW talking about some very strange Staples coupon codes, usually for a specific item. Here is the link.

I also received one email from Staples, in it was a 16-digit code just for 10 off 50 in cartridges.

So is this an indication that Staples has changed its code-assign method?

I post this in this forum, don't know how many people can actually see this.

Not sure what you mean by strange but the coupons the OP posted were sent out with the quarterly business rewards statements. I've got quite a few of those.

As for the 16 digit codes, Staples started this last year I believe.

The new code I got from email were $10 off $50 purchase of cartridges. The ones I used to have were like $10 off $40 of anything. That's the difference, I think.

That's just a different promotion. Staples has sent out $10/50 off cartridges in the past..