Roeloffs quickly became the expert on tax issues in the Hamburg State Administration and belonged to the Deputation until his retirement in 1913.

Roeloffs was considered to be economically educated, since he was in the years 1864 to 1868 listener to the public lectures of Adolf Soetbeer and Ludwig Aegidi in Hamburg.

In May 1879, the Imperial Chancellor asked the Hamburg Senate to accede to the German Customs Union as provided for in Article 34 of the Constitution.

The Senate rejected this, citing the effect on the city's maritime trade, especially with the new high external tariff of the Customs Union.

[3] In the autumn of 1880, Roeloffs, with senators Versmann and O'Swald, and Arthur Lutteroth, made a fact-finding journey to Antwerp, Rotterdam, Amsterdam, London, and Liverpool, in order to clarify the basis on which Hamburg could negotiate terms with Prussia.

On 25 March 1881, Versmann proposed to the Senate of Hamburg and the Imperial Government that real negotiations should begin.

In the period remaining prior to Hamburg's accession to the Customs Union in 1888, sufficient space had to be created on the free port area for the storage and processing of the goods, which had previously been spread over the entire urban area of Hamburg.