Fine, except that it doesn’t work that way. All Representatives are up for election every two years, but the House is not involved in Senate confirmation hearings so no Republicans or Democrats will be kept off the campaign trail by Senate hearings.
There are 33 Senate seats up for (re)election in 2018, 24 Democrats (including 2 Independents) and 9 Republicans, so considerably more Democrats than Republicans will be kept off the campaign trail by Senate hearings in October. In addition, there are 2 special elections to fill vacated Senate seats, one in Minnesota and one in Mississippi. Consider this a wash.
So there is definitely an advantage to the Republicans by keeping the Senators up for reelection in Washington in the last month of the campaign since the Democrats have to defend 24 seats while the Republicans only have to defend 9.