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Very simple. Chronologically this happened. Let's assume every person bid on only 1 lot, not multiples, for simplicity of explanation:
1. Auction opens. There are 175 lots available, $39.99 minimum allowable bid, no bids yet.
2. 140 people place bids, each starting at $39.99 (optionally with a secret AutoBid max amount).
3. There are now 35 lots remaining with no bids on them whatsoever, and a $39.99 minimum bid.
4. You come along and place a bid on one of those 35 lots, inexplicably using a starting bid of $42.99 (optionally with a secret AutoBid max amount).
5. There are now 34 lots remaining with no bids on them whatsoever, and a $39.99 minimum bid.
6. Other people come along and place starting bids of $39.99 (optionally with a secret AutoBid max amount) on those 34 lots.
In other words, you only irreversibly raised the "bid floor" on YOUR OWN lot, not all of them. There was NO reason for you to do this whatsoever, you should've used a starting bid of the minimum possible amount, in this case $39.99, and then set your AutoBid max to the maximum amount you'd be ultimately willing to pay. NEVER set your STARTING bid to the maximum you're willing to pay, ALWAYS set it as low as the system will possibly allow!
You could have irreversibly raised the "bid floor" for ALL remaining lots, but to do that you would've had to place either a starting bid or an AutoBid max of $42.99 on ALL 35 REMAINING LOTS. That would be the only way to do it, and obviously that's very expensive to do, unless others later exceed your bids on many or all 35 of those lots.
Read up some more on how multiple-lot auctions really work, and you'll understand fully.
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