Hmm, i thought it had one less, oh well. That said, 5-4 will bring you a lot less gardens so it really depends on whether you need faster levels or more gardens. I used to make the gathering my line. Once that one more gather was available i had to level. When neither 5-4 or 2-1 can level you at once i recommend making that your goal as well, since it means wasting less gathers.