Non deductible contribution to tIRA, then rolled it over to Roth IRA. In the same year, later rolled over from a previous employer's 401K to the same tIRA. Taxable?

I made a non deductible contribution of 5500 to traditional IRA and then rolled it over to Roth IRA in 2016. In the same year, later I rolled over about 2200 from a previous employer's 401K to the same traditional IRA account. After filling up all the details in TurboTax desktop, the line 15b in 1040 shows taxable amount of $1600. Line 16b shows $0. Would this be accurate? 

After reading various answers it seems when I rolled over from traditional IRA to Roth, it presumable rolled over partial (& proportional) rolled over 401K amount which in turn became taxable. Is that correct assumption? 

If above is correct, that'd mean tax has been paid on some of the amount held in traditional IRA ($1600 to be precise). Is that accurate too? Do I need to show it on the tax return?    

Thanks!