If "contractual changes" refers to changes or amendments to an existing contract, where the contract has already been "awarded," then registration would not be required as these types of communications fall outside the scope of the rule. In order for the registration requirement to kick in, the communications must be made for the purpose of influencing the "award" of a contract, lease, etc. If the communications concern the "administration" or "amendment" of an already existing contract, that would not be "executive branch lobbying." This answer would be the same regardless of whether changes to an existing contract involved monetary consideration or not.
For more information, see the Executive Branch Lobbyist Registration Rule, visit the Executive Branch Lobbyist website at http://www.in.gov/idoa/2885.htm, or call (317) 234-4431.