Older pledge limits and Amazon

Question:

When we increase a our pledge, it creates a new pending payment pledge limit in your amazon account which has the same "active" rating and time limit to be charged as the new one.

Should we delete the old ones with incorrect limits? Theoretically it looks like they could still be charged.

I just re-pledged after disabling all my older limits. I doubt it's an issue, but I really decided to pledge a little less than initially, and din't want to end up overdrawn because something glitchy went wrong at Kickstarter.com.

If you value your backer number, you may want to only remove your older limits.

Yeah, I figured as much.

Another concern if anyone can answer,

When the kickstarter is officially over, are we charged the full pledge limit automatically or do we get a survey specifying what we want, and anything left unused/unclaimed isn't charged(say I decide not to get that extra usb after all)?

Sorry for the nooby questions, never participated in a Kickstarter before.

We get charged by kickstarter, so the full amount we pledged.

This is independend from the Survey, I am sure.