I've made solid progress and have the following to report.
The main problems come from creating server-side validation and then updating or adding to the values/fields being validated.
What happens is that the numeration for the individual identifiers gets jacked up:
Non-sequential additions.
Added spaces in the naming numerations and as mentioned, one time there was no numerical numeration appended at all.
The attached screenshots show how DW and the extension created the code as well as the now working instance where hand-coded changes made things uniform.
For instance, in the following example we see a space inserted before the numeral 4. And the second line is numerated as #2 though it should have been a sequential #5
$WAFV_Errors .= WAValidateRQ(((isset($_POST["dateDepart"])) ? $_POST["dateDepart"] : "") . "", false, 4);
$WAFV_Errors .= WAValidateRQ(((isset($_POST["persons-qty"]))?$_POST["persons-qty"]:"") . "",false,2);
The other screenshot shows the page having met all server-side variables, and now successfully showing a summary of the costs, but losing all it's prior populated field values as the behaviour has successfully processed. So I may need to move to saving the field values as $_SESSIONs or remove the code from wavt_validatedform_php.php or wavt_scripts_php.php that is clearing those prior useful values (example: <?php echo(isset($_POST["fail"])?$_POST["contactName"]:ValidatedField("ratesandavailabilityx_815", "contactName")); ?>).
Lastly and probably a DW issue, when updating, there are multiple cases of the require_once files:
<?php require_once("webassist/form_validations/wavt_scripts_php.php"); ?>
<?php require_once("webassist/form_validations/wavt_validatedform_php.php"); ?>
<?php require_once("webassist/form_validations/wavt_validatedform_php.php"); ?>
Any of these examples where purely DW and Server Validation Behaviour generated.
Latest dev iteration is here: https://hotellecabanon.com/rates-and-availabilityy