Maximum order amounts, defined in USD terms and applicable to all coins in the Voyager app, are set on a coin-by-coin basis and may change from time to time. They are set at the maximum amount at which Voyager has determined it can fill an order at one of more of its routing destinations given the liquidity available for the coin and the bid x ask prices in the app, which Voyager honors up to the maximum order size (regardless of whether Voyager is actually able to fill the user's order at that price or better).
Voyager routinely analyzes bid x ask spreads and maximum order sizes in the context of the liquidity available for each coin and its price. If it is determined that Voyager can tighten spreads or increase maximum order sizes while still being able to fill most maximum order size orders at the quoted bid x ask price or better, the spreads are tightened or the maximum order size is raised.
Voyager is working on improved UX to communicate maximum order sizes and also a more dynamic method of determining the proper mix of spreads, max order sizes, cash back and fill prices/price improvement.