174276 = 15 + 174246 + 15

That's the number of raw frames encoded on the disc (what you'd get using 'Ignore' option in DGIndex.)

Using 'force film' you get

174270 = 12 + 174246 + 12

So I'll respectfully disagree with Chew, there's non-film bits at both ends.

The first 15/12 comprise PGC_2 which is located at the head of the first VOB.

The last 15/12 are the last cell of PGC_1 (IfoEdit calls it Cell51) at the tail of VTS_03_7.VOB

For those interested in frame counting, be sure to try DGIndex's feature
"Tools --> Parse D2V" and then read the parse.txt file it generates.
The non-film bits at beginning & end can be spotted easily, even by a rookie like myself, because there's no asterisks.