To value Vault Shares, Notional needs to convert the value of the strategy assets to the primary borrow currency.
For example, in the context of a Balancer two token pool vault strategy, Notional will need to look at the vault's underlying claims on the pool. It then converts these claims to the primary currency using the pool's spot exchange rate.
Oracle Price Deviation Limit Percent
To ensure that the spot prices used during the vault shares valuation process are accurate Notional compares the implied spot prices of the pool's underlying currencies to chainlink oracle prices. For example, if the vault's strategy is to LP in a wstETH/ETH pool, Notional will calculate the pool's spot exchange rate between ETH and wstETH. It will then compare this exchange rate to Chainlink. If the deviation between the spot exchange rate and chainlink exceeds the allowed Oracle Price Deviation Limit Percent parameter, then vault transactions will revert.