Witr and Nawaafil

Salaatul Haajat

Q: I heard that if one prays two rakaats salaat e Haajat at Tahajud time and in the first rakaat after sura e fatiha one recites Rabbana Ateena
fid dunya Hassanato Wafil Aqirat e Hassanaton Wa Qina Azaabun Naar. Only this Ayat countinously as much as he can if possible 1/2 - 1 hour and do the same thing in the second Rakaat and after finishing the salaat and salaam and recites the same Ayat unlimitedly while sitting and after that he prays for any purpose it will be accepted, when I heard this I decided to recite this Ayat for at least 5 minutes in both Rakaats if I could'nt recites for One hour.  Please Advice me on this. JazakAllah.

Ishraaq and chaast salaah

Q: Is ishraaq and chaast salaah the same or we should read both because I am regularly reading ishraaq but chast I read some times. Someone said it is the same, if you read it in the early morning it is ishraaq and if you read it later than it is called chasit. Please explain.