Matching one to many and aggregating

Hi All,

I'm running powerBI across two spreadsheets, it's the weekly CRM Opportunity ID extract.

Table 1 is "Latest" and Table 2 is "Previous".

I want to do a mapping and connection of "NewOps", (ops which were not in the particular extract last week but are now.  This could be either because they're brand-new ops, or else they're ops which were not expected to close in the selected time horizon but now are).

The challenge is that there is not really a unique matching because there will be multiple records for each unique "Opportunity ID".

e.g. Table 1 may have 3 entries for Acme Bank 

Opp12345 | Acme Bank | Total Value $120 | Solution Value $00

Opp12345 | Acme Bank | Total VAlue $0   | Solution 1 Value $40  | Field A

Opp12345 | Acme Bank | Total Value $0   | Solution 2 Value $55  | Field B

Opp12345 | Acme BAnk | Total VAlue $0   | Solution 3 Value $25  | Field A

Opp23456 | BCME Shop | Total VAlue $57  | Solution 1 Value $25  | Field A

I created a table called "NewOps" which uses.

NewOps = EXCEPT(VALUES(Latest[Opportunity ID]), VALUES(Previous[Opportunity ID]))

It has columns in it such as 

NewSolVal = CALCULATE(VALUES(Latest[SolVal]), FILTER(Latest,NewOps[Opportunity ID] = Latest[Opportunity ID]))

The Trouble is... 

The report works if I use "remove duplicates" in the query on OppID, and it will show the new Opps, but then it won't show the full SOLUTIONVALUE, because it will only pick up the first record.

If I take away "remove duplicates", then the visualisations fail

A table of multiple values was supplied where a single value was expected.

is there a better way of doing this ?   thanks!