As per my experience better you stress on understanding of provisions....solutions to problems will automatically come.
Taxation problems are nothing but set of provisions and if time permits u can also solve problems. But understanding of provisions is enough to crack dt paper....
solving too many sums may create a problem for u while revising before exam.....
in dt paper there is 40-55 marks theoritical questions related to provisions and other matters for which u have to cover the entire syllabus comprehensively.
for problem part u can solve past papers with last 3 RTP's.