How quartus duplicate registers by Synthesis Attributes (Verilog-2001)?

I am using Quartus Standard 16.1.

I have 5 modules like this:

top_mod

|--> mod1

|--> mod2

|--> mod3

|--> mod4

All of them are sharing the same clock and reset signals.

By using timing closure tool, it is highlighted that some registers in mod1, mod2 and mod3 have high fan-out values resulting -ve slack value and fail to meet the timing requirement.

I tried to insert Synthesis Attribute (*maxfan=10*) to those highlighted registers. Some registers are show up in the "Registers Duplicated to Honor Maximum Fanout Requirement" report but not all of them.

It is found that the report is always show duplicated registers up to TEN (10) records only.

1) Is it the report problem? (that showing up only the top 10 records).

If it is the case, how to verify which registers are being duplicated?

2) or quartus will duplicated registers up to n registers only? how to hint quartus to duplicate more registers?

Regards,

Ken