«لَوْ شِئْتَ أَنْ تُعْطِيَ دِرْهَمًا أَعْطَيْتَ دِرْهَمَيْنِ»
Had you wished to give one dirham, you would have given two.
The first object «درهما» supplies the comparison against which the second «درهمين» is evaluated. The contrast in amount is the point, so “Had you wished, you would have given” cannot express it adequately.
This shows the difference between ellipsis being grammatically possible and rhetorically suitable. If the communicated distinction depends on a named amount or class, suppressing the object may sacrifice the intended information.