4 place decimal discount rate

We have products that sell for $6.99 each but we want to offer a discount to $5.00 each if you buy five or more.

Currently, we are limited to two decimal paces for the percentage discount rate such as .29. This causes the price to range depending on how many above 5 units they purchase and we cannot advertise the $5/ea rate as it could be $5.07 or more or less.

Is there any way we can modify the plugin to accept six decimal places so we can enter in the discount rate of 0.284692. This way we cab offer 5 or more for $5.00 each.

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