There is a Standard Pay Plan and an Executive Pay Plan for this State, as established by the Secretary with the approval of the Governor and as amended or adjusted in accordance with this subtitle. The purpose of the pay plans is to provide employees in positions that involve comparable effort, knowledge, responsibilities, skills, and working conditions with comparable pay according to the relative value of services to be performed. A pay plan is effective for a fiscal year only to the extent that sufficient money is available in the State budget for that purpose.