This: "get an adjustment to income for contributions to an HSA if they used disbursements only for medical expenses?"
Is a NO.
Your question makes no sense. You asked two things that do not relate to each other.
Disbursements are either Medical, or not. If Not, they will be treated as taxable income. It has nothing to do with Contributions.
Contributions need to qualify as Pre-tax to be made at all. That's because it Quailfies based on all the regulations (the account owner is covered under a HDHP that meets the HSA requirements, the account owner is not on Medicare, etc) and the amount is not over the annual limit for that person, taking into consideration the amount contributed from all sources are treated in aggregate for the limit test. That is what goes on the 8889 for the taxpayer or one for the Spouse, not combined but separate forms.
"Level Up" is a gaming function, not a real life function.