I have 3 outstanding re-creatable Linkpoint API errors. Each slightly different in their basket make-ups. A customer encountered this combination yesterday:

Error Message:

Subtotal miscalculation. Please notify the storeowner.
SGS-002301: Charge total must be the sum of subtotal, tax, value added tax, and shipping.

Linkpoint Debug Data - FAILURE
Sep-15-2008 03:12:29
=================================

Response Code:

Sending to Gateway:
result = LIVE
oid = 1071-VnvCJQ
ip = <removed>
ponumber =
subtotal = 39.425
tax = 0
shipping = 4.95
chargetotal = 44.375
cardnumber = ******
cardexpmonth = 11
cardexpyear = 08
cvmindicator = provided
cvmvalue = ******
userid = 552
customerid = 552
name = <removed>
company =
address1 = <removed>
address2 =
city = <removed>
state = Arizona
country = US
phone = <removed>
email = <removed>
addrnum = <removed>
zip = <removed>
sname = <removed>
saddress1 = <removed>
saddress2 =
scity = <removed>
sstate = <removed>
szip = <removed>
scountry = US
comments = Website Order
ordertype = SALE
host = secure.linkpt.net
port = 1129
keyfile = /home/admin/public_html/includes/modules/payment/linkpoint_api/<removed>
configfile = <removed>
transactionorigin = ECI
terminaltype = UNSPECIFIED


Result:
(
[r_csp] =>
[r_time] => Mon Sep 15 16:12:32 2008
[r_ref] =>
[r_error] => SGS-002301: Charge total must be the sum of subtotal, tax, value added tax, and shipping.
[r_ordernum] => 1071-VnvCJQ
[r_message] =>
[r_code] =>
[r_tdate] =>
[r_score] =>
[r_authresponse] =>
[r_approved] =>
[r_avs] =>
)

I have set up a testing database where I took this customer's order configuration and was able to re-create her error as well as the previous errors.

The other error is located in this thread:
http://www.zen-cart.com/forum/showthread.php?t=103208

This latest instance is the most simple in construct. No sales tax and no coupon codes involved. No sale products either.

I'm really hoping someone can get to the bottom of this.

As a side question: Should I consider dropping my credit card provider and finding a new one that uses a different API?

Thank you!

Kathy