Standard price is a concept used to coordinate the specific price movements of PLVTs, it's much easier to find out the how the system rebalances the leverage level of PLVTs.
Standard price is the price at each day's UTC 0, if there is no intraday rebalance.
intraday rebalances will happen only if price movement reaches a certain level, usually 10%.
For example, if BTC price at UTC 0 is 100, and rises to 110 in the same day, then the rebalance happens, 110 is the new standard price.
If there is no intraday rebalances, therefore intraday price movement < 10%, the standard price will be the price at 00:00:00 UTC. If the intraday movement is >= 10%, then there will be an intraday rebalance, making the last standard price to be 110% of the old standard price.
at 00:00, BTCUP standard price = 100, BTC standard price = 10,000. In a few hours, BTC price rises by 2% , then BTCUP will trade at "Standard Price * (1 + 2% * 3) = 106. ". If BTC goes up another 1% , then BTCUP will trade at "Standard Price * (1 + (1% + 2%) * 3) = 109".
If the price does move to 11,000, which triggers the 10% threshold, then 11,000 will be the last standard price for BTC. At this moment, price of BTCUP = 100 * 1.3 = 130.
Furthermore, BTC price continues to raise to 12,100.
12,100/11,000 -1 = 10%, means using 11,000 as standard price, another 10% move happens.
At this time the BTCUP price will be, 130 * 1.3 = 169.