Block numbers under head pgbp

Hi there,

As we know that u/h Profits and Gains from Business & Proffession(PGBP), DEPRICIATION RATES FOR TANGIBLE ASSETS & INTANGIBLE ASSETS are divided in form of BLOCKS. However i m refering GIRISH AHUJA SIRs' book and the BLOCK NUMBERS in BOTH the books (ICAI STUDY MATERIAL & GIRISH AHUJA SIRs' BOOK) is different. 

Say for example In GIRISH AHUJA SIRs' book

BLOCK No. 1 (under sub-heading Machinery and Plant)  is for - MOTOR CARS OTHER THAN BUSINESS OF RUNNING THEM ON HIRE

and SAME in ICAI STUDY MATERIAL is BLOCK No. 5. Under same sub-heading.

Can block numbers vary under the four sub-headings namely Plant and machinery,Buildings & Furniture&fittings AND Intangible Assets under head PGBP for claiming depriciation.

Please help. 

I am very confused and tensed. Its high time, exams are on head and i got stuck in this foolish confusion.