The phrase "a higher grade of" is correct and usable in written English.
It can be used when referring to a superior quality or level of something, often in comparison to others.
Example: "This restaurant is known for serving a higher grade of beef than its competitors."
Alternatives: "a superior quality of" or "an elevated level of".
The available two-tone interior and a higher grade of metallic trim add some distinction.
Meanwhile, I gave Mitt Romney, his primary rival for the Republican nomination, a higher grade of A-minus.
All this transformed Radcliffe into a higher grade of star in Britain, which only further magnified the Olympic disappointments to come.
But keep track because if you cheat, either by buying a higher grade of gas than you specified or getting too many gallons, the company will charge you a $1.50 service fee.
The Iranian president, Mahmoud Ahmadinejad, said Wednesday that his nation would produce a higher grade of nuclear fuel on its own, escalating its war of words with the international community over its disputed nuclear program.
Alrosa produces more carats of diamonds annually than De Beers, but De Beers has higher revenue, earning more from each stone as its mines yield a higher grade of gem.
If the plan receives the financing and approvals that are still needed, merchants say, the wharf will attract a higher grade of shops and more visitors, including skeptical San Franciscans.
The company chose not to use the type of raised-floor air ventilation system that Ford has in its Irvine building, but compensated for omitting that particular energy-saver by using a higher grade of low-emission window glass, said Dan Heinfeld, the president of LPA.
Though it aspires to a higher grade of pulp, Nocturnal Animals makes a rather good companion piece to this autumn's multiplex phenomenon The Girl on the Train, a largely standard-issue whodunnit that reveals a far more interesting gendered subtext once the machinations of its critical twist are laid bare.
A higher grade of echogenicity with reduced bone signal correlates with the severity of myopathy [17].
Interestingly, a higher grade of concern before hysteroscopy has been reported among infertile women [50].
