As the Loan-to-Value figures for assets differ, they act cumulatively to allow borrowing. For example, if a user were to supply $1000 USD of ETH and $1000 USD of SPELL, the amount of value they could borrow would be $1600 USD, as while the Loan-to-Value figure for ETH is 85%, SPELL has a Loan-to-Value set at 75% ($850+$750=$1600).