Gupt Singh jeeo
according to Mahan Kosh, (page 505 and 667) japee is more the physical action of japping naam and 'dhiyayaing' naam is more mind concentrating/meditating on naam
Japeeਨਾਮੁ ਨ ਜਪਈ ਕਿਉ ਸੁਖੁ ਪਾਵੈ - Without chanting the Naam, how can he find peace?
Dhiaeeਨਾਨਕ ਨਾਮੁ ਧਿਆਈ ਹੇ - Nanak meditates on the Naam
ਜਿਸ ਨੋ ਕ੍ਰਿਪਾ ਕਰੇ ਪ੍ਰਭੁ ਅਪਨੀ ਸੋ ਜਨੁ ਤਿਸਹਿ ਧਿਆਈ ਹੇ - That humble being, unto whom God grants His Grace, meditates on Him.
ਆਤਮੈ ਹੋਇ ਧਿਆਈ - Let your soul meditate on God.
Daas believes that Guru Sahib is saying do both; physically jap naam as well as mentally concentrate what we are meant to - what the panj pyarai have told us to concentrate on.
Seems to be telling us that both are required not just one, reminds me of the sakhi where Guru Nanak Dev Jee was with those who did not fully concentrate on their namaaz and reminded them to not only pray physically but also mentally.