I've used both Dicor 501 and Alpha Systems TPO lap sealants on TPO roofs. I can't tell the difference.
Dicor says their 501 lap sealant will work on "most TPO roofs" and it seemed to on my 2010 Roo, but they do make a self-leveling lap sealant specifically for TPO roofs. Their standard lap sealant is 501 in a green tube but they also have a product called ultra-sealant in a blue tube. The ultra sealant also comes with a primer but it may not be needed if you're touching up existing cracked sealant.
2011 Rockwood Signature Ultra Lite 8293SS, 12K Equal-i-zer
2016 Ford F-250 XLT SuperCrew, 6.2L, 4x4, 6'9" bed, 3.73
2010 Rockwood Roo 23SS (2012 - 2014)
2009 Ford F-150 XLT SuperCrew, 5.4L, 4x4, 5'6" bed (2012 - 2016)