Seems reasonable, but the cost and the purpose should be placed transparently in the budget. OPA should not be keeping excess funds for some unknown, unapproved purpose. The very purpose of a budget and the very public process involved is to be sure funds are collected to do what the budget proposes - nothing more, nothing less. 

The best OPA budget, as is more or less mandated, is one where the budget is net zero exactly at the end of the fiscal year. Budgets can be manipulated. For example, include employee positions that are not filled. 

If, as you suggest, aesthetic improvements are needed, the cost for any specific improvements should be placed in the budget.

To do otherwise is subterfuge.