The phrase "additional discretionary" is correct and usable in written English.
It can be used in contexts where you are referring to extra choices or options that are not mandatory but can be exercised at one's discretion.
Example: "The committee has the authority to allocate additional discretionary funds for special projects."
Alternatives: "extra optional" or "supplementary discretionary".
In addition, the system permits additional discretionary information in the form of comment boxes which allow the addition of clinical comments (see also Figure 1).
The chancellor said councils would be allocated additional discretionary housing payment funding.
A sensible fiscal regime would allow scope for additional, discretionary loosening of fiscal policy.
"Some producers out there don't want to sell additional discretionary gas to Enron, so they're having to pay up".
He will also receive an additional discretionary payment of $1.5 million in restricted shares, which will vest over two years.
As the Guardian's housing network has highlighted, some councils are trying to help tenants with additional discretionary payments, but there simply isn't enough money to help everyone.
Yesterday's order was billed by the Obama Administration as a generous addition to what the law requires, a "discretionary" additional annual review that the government will provide to prisoners it has deemed too dangerous to release and therefore detainable until (and if ever) this far-reaching war "against al Qaeda, the Taliban and associated forces" is over.
The surprise was the overall size and also dividing it into two elements, the core and an additional $10 billion for discretionary items.
Trump, to extend the current spending bill that is set to expire in late April, would allow an additional $10 billion in discretionary spending.
Texas cut $4 billion in state funding and an additional $1.4 billion in discretionary grants to public schools during the latest legislative session — a big hit.
This week, the union agreed to drop the measure after the governor proposed an additional $1.8 billion in discretionary spending for education, intended to compensate for the lean years of the early 1990's, when teachers were forced to do without cost-of-living increases in wages to help close looming budget deficits.
