I can see the gap only when I start a new bot, bot not on a running arbitrage bot.
Price gap usage is only for when you starting and closing a position. After it is running, you can see the unrealized profit. This unrealized profit is coming from the current price gap vs your initial price gap. If current price gap is LOWER than your initial price gap, this unrealized profit will become POSITIVE for you. If current price gap is HIGHER than your initial price gap, this unrealized profit will become NEGATIVE for you.