Is the Ancestry PCC wills index different from TNA's?

The newly available database England & Wales, Prerogative Court of Canterbury Wills, 1384-1858 on Ancestry.co.uk is apparently based on a new index. The data below compares results for searches for some of the surnames in my family tree.

Surname/Ancestry exact/Ancestry default/TNA
Allcroft/2/10/3
Blore/12/100/11
Digby/106/119/114
Lewis/1,920/5,717/2,021
Northwood/9/9/11
Ordish/4/4/4
Price/1,856/2,146/1,909
Smith/11,242/12,652/11,655
Wilson/2,507/3,001/2,596

The number of entries is not the same. The Ancestry index is not copied from TNA's. That's good. Usually TNA will include a few more entries than the Ancestry exact search and fewer than Ancestry's default search.

For Ancestry subscribers the best advice is to use both indexes, then see if you can find the original image for any entries not found by Ancestry using the reference information given from the TNA search.