It can be, but because offensive rebounds don't create another possession, but are part of the original possession, you can shoot a very middling field goal percentage but still post a high efficiency. If you want to see if a team is getting good high percentage shots, just look at team field goal percentage and points in the paint (which can come in transistion or on post ups). Right now (and even last year when they were so "efficient") they had a very mediocre field goal percentage and have always been close to dead last (or dead last) in points in the paint and transition buckets.
I am not buying this one bit. If you have good 3P shooters - giving them open 3P shots is an easy bucket. If you have players that are good in ISO situations, giving them the system where they can do that is getting good shots.
Just for an example, if we look at Portland's TS% - this year, with all the turmoil, we sit at a 54.5% - which is 12th in the league. If you look at our TS% from last year, and put it in the list for this year (I do not have TS% for the entire league from last year, so I calculated it for last year for the Blazers and put it in the list of this year's teams) - last year's Blazers TS% would put them 7th in the league.
Last year's team had 6 rotation players with TS% over 55% - which is fantastic (S-Bo also had more than 55%, but I eliminated him from the list). There is just no way so many rotation players had such high TS% if they did not get easy shots. These might not be easy shots in the "Shaq, 1ft from the basket with Frye guarding him" type - but if non contact drawing players like Blake, Rudy and Nic had over 55% TS% - they were getting easy shots.
If you look at our rotation players with over 1000 minutes last year, only one of them had a TS% of less than .500 (He is now a member of the Kings, for those who do not know it). For the record, LMA and Travis, which are the other 2 rotation players under 55% were not bad as well, with Travis at .541 and LMA at .529
Just as a comparison, the LAL, your NBA champions last year, had only 5 players over .55 in TS%, if you remove the 2 non rotation players (arbitrarily set as 1000 minutes) - they are down to 3.
This team gets enough easy shots. Sure, it would be nice to get some more back to the basket shots - but Greg's improvement helps in this regard, and JB's attack with no mercy attitude is another thing that will help this team.
Conclusion, the high efficiency offense was an indication that the team got enough easy shots. The problem is, and was, more on the defensive end of the court - and last year in the playoffs, their inexperience and a tough matchup exposed some of the obvious issues they had. But, they are clearly on the right track, health permitting, to be a contender - as far as the roster is concerned.