docs: update copy

Author: kgryte

spec/draft/API_specification/array_object.rst

@@ -179,9 +179,9 @@ A conforming implementation of the array API standard must provide and support a
 
 An in-place operation must not change the data type or shape of the in-place array as a result of :ref:`type-promotion` or :ref:`broadcasting`.
 
-Let ``x1 += x2`` be a representative in-place operation. If, after applying type promotion (see :ref:`type-promotion`) to in-place operands ``x1`` and ``x2``, the resulting data type is the same as the data type of the array on the left-hand side of the operation (i.e., ``x1``), then an in-place operation must have the same behavior (including special cases) as the respective binary (i.e., two operand, non-assignment) operation. In this case, for the in-place addition ``x1 += x2``, the modified array ``x1`` must always equal the result of the equivalent binary arithmetic operation ``x1[...] = x1 + x2``.
+Let ``x1 += x2`` be a representative in-place operation. If, after applying type promotion (see :ref:`type-promotion`) to in-place operands ``x1`` and ``x2``, the resulting data type is equal to the data type of the array on the left-hand side of the operation (i.e., ``x1``), then an in-place operation must have the same behavior (including special cases) as the respective binary (i.e., two operand, non-assignment) operation. In this case, for the in-place addition ``x1 += x2``, the modified array ``x1`` must always equal the result of the equivalent binary arithmetic operation ``x1[...] = x1 + x2``.
 
-If, however, after applying type promotion (see :ref:`type-promotion`) to in-place operands, the resulting data type is not the same as the data type of the array on the left-hand side of the operation, then a conforming implementation may return results which differ from the respective binary operation due to casting behavior and selection of the operation's intermediate precision.
+If, however, after applying type promotion (see :ref:`type-promotion`) to in-place operands, the resulting data type is not equal to the data type of the array on the left-hand side of the operation, then a conforming implementation may return results which differ from the respective binary operation due to casting behavior and selection of the operation's intermediate precision. The choice of casting behavior and intermediate precision is unspecified and thus implementation-defined.
 
 .. note::
     Let ``x1`` be the operand on the left-hand side and ``x2`` be the operand on the right-hand side of an in-place operation. Consumers of the array API standard are advised of the following considerations when using in-place operations: