I wanted to look at occurences of the phrase "νυνι δε" in Paul's writings so used the following search in NA27 (I have defined Pauline Letters as Romans to Philemon for the sake of this search)

This gave me 32 results in 16 verses.
I wanted to see how this aligned to the New International Version and so did the same search (as below)

As you can see, the NIV search came up with 26 results in 13 verses:
Trying to understand why I looked at the way the verse is laid out in the RI and found the following:

While the coding shows that it knows the order of the words is "νυνι δε" it is shown in the panel in the reverse order. I assumed this was why it was not showing a match.
However, when I checked one of the places which did get a hit I found the same ordering (Romans 3:21) for example) so that couldn't be the reason.

If I try the same search against the ESV I get a different set of results again compared with the NIV. It has 24 results in 12 verses:
- it matches Romans 7:17 which the NIV does not
- It doesn't have 1 Corinthians 12:18 which the NIV does
- It has 2 Corinthians 8:11 which the NIV does not
Does anyone have any explanation as to why I am getting these different results?
Many thanks
Graham