Field value query and filed range query, result not matching

Question

I am getting different result when I execute below query, cts:field-value-query is returning 10355058 count and cts:field-range-query or cts:path-range-query is returing 12189408 count, so I am not sure why is this difference in count ?.

let $query1 := cts:field-value-query("item",("A", "B"))
let $query2 := cts:field-range-query("item", "=", ("A", "B"))
    return (  
            xdmp:estimate( cts:search(fn:doc(), $query1)), 
            xdmp:estimate( cts:search(fn:doc(), $query2)) 
            )

Answer 1

Thank you for your valuable comments, following query worked and got correct result by applying ('unstemmed') query option.

let $query1 := cts:field-value-query("item",("A", "B"),('unstemmed'))
let $query2 := cts:field-range-query("item", "=", ("A", "B"))
    return (  
            xdmp:estimate( cts:search(fn:doc(), $query1)), 
            xdmp:estimate( cts:search(fn:doc(), $query2)) 
            )