The phrase 'only at the level' is correct and usable in written English.
You can use it to refer to the degree of something. For example: "My understanding of the topic is only at the level of a beginner."
"The Adjustment Bureau" works well only at the level of craft.
Years ago, China's filtering could operate only at the level of a server's IP address.
Until now, however, such control could be exerted only at the level of the entire organism.
Give staff a pay rise, even if only at the level of CPI inflation.
We'll also make use of matrix algebra, but only at the level of matrix multiplication and matrix-vector products.
"If it is seen as the party of law and order only at the level of street crime, it will misserve the public".
We have at this point in human history evolved fairly good democratic political institutions, but only at the level of the nation-state.
An erroneous legal standard for determining the admissibility of allegedly coerced confessions was interjected into the proceeding only at the level of the Supreme Court of California.
And when Congress reaches a budget stalemate, the District must switch to the equivalent of austerity spending, funding agencies only at the level of the previous year.
Investors need to consider that while bond yields have risen (and prices have fallen) they are still only at the level seen last Christmas.
When business does come back it will be only at the level of five years ago, believes another senior investment banker.
