Please review transactions behavior below:

Authorize.NET (is not supported in 1.8.5.0 and newer)
Changes made with Order Manager What happens
authorized amount increases old transaction becomes voided, new transaction is created instead
authorized amount decreases nothing changes, but when invoice is created, correct amount is captured
authorized amount stays unchanged nothing changes
captured amount increases additional amount is authorized
captured amount decreases old transaction becomes voided, new transaction is created instead
captured amount stays unchanged nothing changes
settled amount increases additional amount is captured
settled amount decreases costs are refunded in authorize.net
settled amount stays unchanged nothing happens

 

Changes made with Order Manager What happens
authorized amount increases old transaction stays unchanged, additional amount is being captured
authorized amount decreases nothing changes, but when invoice is created, correct amount is captured
authorized amount stays unchanged nothing happens
captured amount increases additional amount is captured
captured amount decreases old transaction becomes voided, new transaction is created instead
captured amount stays unchanged nothing happens
settled amount increases additional amount is captured
settled amount decreases refund is created
settled amount stays unchanged nothing happens

 

Authorize.net eCheck
Changes made with Order Manager What happens
authorized amount increases old transaction stays unchanged, additional amount is being captured
authorized amount decreases nothing changes, but when invoice is created, correct amount is captured
authorized amount stays unchanged nothing happens
captured amount increases additional amount is captured
captured amount decreases old transaction becomes voided, new transaction is created instead
captured amount stays unchanged  nothing happens

 

PayPal PayFlow
Changes made with Order Manager What happens
authorized amount increases old transaction is voided, new transaction is created instead
authorized amount decreases nothing changes, but when invoice is created, correct amount is captured
authorized amount stays unchanged nothing happens
captured amount increases old transaction is voided, new transaction is created instead
captured amount decreases old transaction is voided, new transaction is created instead
captured amount stays unchanged nothing happens