you can use findPageList api based on entered ID, it will return ArrayList of same IDs, then convert the ArrayList to ClipboardProperty then use countInPageList on ClipboardProperty based on measures , if count >1 then duplicate measures entered for that id.
ID1 Measure3 Assure after third row user added below row i.e ID1 Measure1
Now use my above explanation ....
first send the list to findPageList by ID1, it will return arrayList with three items like below
ID1 Mesure1, ID1 Measure3, ID1 Measure1
first and third have the same measure. we need to find it by using the countInPageList api
Now use the countInPageList based on measure property. Measure1 is repeated two times and count returns 2. which is >1, then you can say its duplicate mesure for same id.