The concept of "re-quote" per se doesn't exist at the 'free market'/exchange. As liquidity (volume-at-price) is 'consumed' or added, the execution price of a market order will be different from the price at the moment you sent your order. Such 'slippage' can be both positive and negative.

No, there are no 'requotes' with DMA/STP brokers; just bids/asks changing from moment to moment.