Script for Calculating LTV

I'm trying to create a script to calculate the LTV based on several factors. If the TransactionType contains the word "Purchase" then the calculation is the InitialAdvance divided by the minimum of the PurchasePrice and AsIsValue. If the TransactionType contains the word "Refinance" then the calculation is the InitialAdvance divided by the AsIsValue. The ChatGPT script given hasn't worked property for some reason as listed below, hopefully someone can direct me the right way:

(function() {

    // Get the values from the form fields

    var initialAdvance = parseFloat(this.getField("InitialAdvance").value);

    var purchasePrice = parseFloat(this.getField("PurchasePrice").value);

    var asIsValue = parseFloat(this.getField("AsIsValue").value);

    var transactionType = this.getField("TransactionType").value;

    // Variable to store the LTV calculation result

    var ltv = 0;

    // Check the transaction type and perform calculations

    if (transactionType.includes("Purchase")) {

        // Calculate LTV using the minimum of PurchasePrice and AsIsValue

        var minValue = Math.min(purchasePrice, asIsValue);

        if (minValue !== 0) {

            ltv = initialAdvance / minValue;

        }

    } else if (transactionType.includes("Refinance")) {

        // Calculate LTV using AsIsValue

        if (asIsValue !== 0) {

            ltv = initialAdvance / asIsValue;

        }

    }

    // Set the calculated LTV value with appropriate formatting

    event.value = ltv.toFixed(2); // adjust the decimal places as needed

})();