Can one child support case be affected by another child support case?

CAN A PRE EXISTING CHILD SUPPORT CASE SET IN ARKANSAS BE MODIFIFIED BY SEPARATE/ NEW CHILD SUPPORT CASE OPENED IN THE STATE OF MISSISSIPPI?WOULDN'T THAT COUNT AS A CHANGE IN INCOME TO MAKE IT MODIFIABLE FOR BOTH CASES? WHERE BOTH PARTIES WILL HAVE A SET EQUAL AMOUNT DISPERSED BY THE NON COSTODIAL PARENT? IF $350 IS PAID TO THE PRE EXISTING ORDER PER MONTH WILL THE NON CUSTODIAL ALSO HAVE TO PAY $350 TOWARDS THE SECOND ORDER OR WILL BOTH AMOUNTS BE ADJUSTED ACCORDING TO THE NON CUSTODIAL PARENTS GROSS INCOME AND ALL CHILD SUPPORT OBLIGATIONS? OR WILL ONE OBLIGATION BE MORE THAN THE OTHER SIMPLY BECAUSE IT IS PRE EXISTING AND HAS PRIORITY OVER THE SECOND ORDER? HOW DOES THIS WORK WEATHER IF IT IS IN THE SAME STATE OR DIFFERENT STATES. BOTH STATES USE THE SAME CHILD SUPPORT CALCULATING FORMULA YET THE PRECENTAGES MIGHT BE SLIGHTLY DIFFERENT B/C OF COST OF LIVING. NEED ALL PROFESSIONAL ADVICE. MEANING YOU HAVE HAD EXPERIANCE WITH THIS PERSONALLY, AS A COSTODIAL OR NON CUSTODIAL PARENT OR BECAUSE YOU KNOW THE LAW DON'T CARE FOR WHAT PEOPLE THINK OUGHT TO OR SHOULD HAPPEN WANT TO KNOW WHAT WILL MOST LIKELY HAPPEN FROM EXPERIANCE. DOESN'T HAVE TO BE THE SAME STATES OR ANYTHING.